FORM THREE CHEMISTRY EXAMS SERIES

 THE PRESIDENT’S OFFICE MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT 

 COMPETENCY BASED SECONDARY EXAMINATION SERIES 

032/1 CHEMISTRY FORM THREE

TIME: 2 HOURS   NOVEMBER 2022

INSTRUCTIONS

  1. This Paper Consists of Sections A,B nd C
  2. Answer all questions in section A and B and only one(1) question from section C
  3. Cellular phone and any unauthorized material are not allowed in examination room
  4. Write your Examination Number on every page of your answer sheet(s).
  5. The following constant may be useful
    • Atomic masses H=1, C=12, N=14,O=16,Na=23,Mg=24,S=32,Cu=64.
    • Avogadro’s number = 6.02 6.02 x 10 23
    • G.M.V at S.T.P = 22.4dm 3
    • 1Faraday = 96500coulombs
    • 1litre = 1dm3 = 1000cm 3

SECTION A. (20 MARKS)

1. For each items (i)-(x) choose the correct answer among the given alternative and write the letter beside the item number in the booklet provided

(i) Which of the following is the agricultural product made by the application of chemistry?

  1. Yeast D. Pesticide
  2. Drug E. Cement
  3. Clothes

(ii) When methane undergo substitution reaction with excess chlorine .what is the end product

  1. Chloromethane D. Monochloromethane
  2. Dichloromethane E. Tetra chloromethane
  3. Dichloromethane

(iii) An element X is found in period 4; group II of the periodic table .if the element X Undergo the reaction X→X 2+ +2e - ; the electronic configuration of X ion formed will be A. 2: 8:6 B. 2:6 C. 2:8:4 D. 2:8:8:2 E. 2:8:8

(iv) A current of 0.2A was passed through an electrolyte for 16 minutes and 40 seconds .what is the quantity of electricity produced in coulombs.

A. 2000C B. 1000C C. 200C D. 0.2C E. 7686C

(v) Which carbonate is the most stable to heat?

  1. Calcium carbonate D. Zinc Carbonate C. Lead II carbonate E. Iron carbonate
  2. Copper II carbonate

(vi) Skin injury that cause a change in the colour of skin

  1. Bruises B. Bum C. Scalds D. Shock E. Suffocation

(vii) A good fuel is the one which has.

  1. High speed of continuous energy supply D. High carbon dioxide production
  2. High energy value supplied E. High content of non-combustible materials
  3. Low carbon dioxide production

(viii) The region of the atmosphere which contains the ozone layer is called

  1. Mesosphere D. Troposphere
  2. Stratosphere E. Metamosphere
  3. Atmosphere

(ix) Aluminum is said to be amphoteric oxide because

  1. It acts as an acid and also It acts as a base
  2. It acts as a neutral compound
  3. It acts as strong reducing agent
  4. It acts as a basic compound

(x) The main impurities in Nitrogen gas prepared in the laboratory are:-

  1. Water vopour D. Dust particles
  2. Oxygen E. Noble gases
  3. Carbondioxide

2. Match the item in LIST A with a correct response in LIST B by writing the letter of the response below the corresponding item in the table given 

LIST A

LIST B

(i) A gas that forms explosive mixture with air and water

(ii) A gas that forms a reddish brown fumes when comes in contact with air

(iii) A gas that turns lime water milky

(iv) A colorless gas that bleaches moist coloured flower

(v) Only basic gas

  1. Nitrogen monoxide gas
  2. Carbon-dioxide gas
  3. Carbonmonoxide gas  thiodne gas
  4. Chlorine gas
  5. Sulphur dioxide gas
  6. Ammonia gas
  7. Nitrogen gas
  8. Oxygen gas  
  9. Hydrogen gas
  10. Hydrogen sulphide gas

SECTION B. (70MARK)

Answer All questions in this section

3. (a) A stone is said to be a good example of matter. Give two reasons to support this fact.

  1. Outline two significance of chemical symbols of an element.
  2. Explain by giving reasons why:
    1. Laboratory door open outwards
    2. Laboratory floor is rough and never polished
    3. Fume chamber is important in chemistry laboratory

4. (a) Identify the substances by using the following information.

  1. A solid is yellow when hot and white when cold
  2. A colorless gas turns a yellow acidified potassium dichromate paper to green
  3. When water is added to a white powder, the white powder changes to blue crystals
  1. With the aid of an equation in each case, explain what will be observed when
    1. Chlorine gas is bubbled through a solution of iron II chloride
    2. Hydrogen Chloride gas is passed through a jar containing ammonia gas.
    3. A piece of sodium metal is dipped into a beaker of water containing some red litmus paper
    4. Carbondioxide is blown into a test tube filled with lime water.

5. (a) outline three reasons to explain why Carbondioxide is used to extinguish fir

(b) A sample of mass 28.6g of hydrated sodium carbonate ( Na 2 CO 3 .10H 2 O) was heated such that; its water was entily absorbed by 32g of anhydrous copper II sulphate to form a blue compound of hydrated( CuSO 4 .XH 2 O) .find the value of X in the copper sulphate.

6.(a)A student aimed to prepared a gas X by reacting a moderate reactive metal with a dilute acid .use this information to answer the following question

  1. What is the name of the gas X
  2. What is the test of the gas X
  3. With reasons; state the appropriate method of collecting gas X
  4. Write the balanced chemical equation for the reaction.

(b) State four properties that make Aluminium useful in overhead cables

7. (a) Calculate the morality of 5% by weight of a solution of sodium hydroxide

(b) What is the simplest chemical formula of a compound formed when 36g of Magnesium combine with 14g of Nitrogen?

8.. (a) During electrolysis of an aqueous solution of salt of metal M , a current of 2.0A was passed for 32minutes and 10 second .the mass of metal M deposited was 2.24g.

  1. On which electrode was the metal deposited
  2. Calculate the amount of charge needed to deposit 1mole of metal M
  3. Calculate the charge carried on the ion
  4. Write an ionic equation to show how the ion of metal M are discharged at the electrode (R.A.M of metal M is 112)

(b)During electrolysis of brine .Sodium is deposited at the cathode and chlorine gas is released at the anode .if 2.0g of sodium are collected at the cathode .find the volume of chlorine released at S.T.P.

9. (a) State the le-chatelier’s principle

  1. State what will happen in the process of equilibrium involving the equation

2SO 2 (g) + O 2 (g) ⥫⥬ 2SO 3 (g) ∆H = -94.4KJMol -1 If

  1. Temperature is lowered
  2. Pressure is increased
  3. The concentration of SO 3 is removed from the system.

(c)Briefly write one application of le- chatelier’s principle.

9. (a) States any three main physical properties of water and show the usefulness of each property

(b)During large – scale treatment of water, what two chemical are added at various stage?. Explain their use.

10. (a) i. Extraction of metal is said to be reduction process. Explain

ii. Why Sodium is collected by upwards in the down cell?

(b) Describe the use of each of the following during extraction of sodium

  1. Calcium chloride
  2. Steel gauze
  1. Name the ores commonly used in the extraction of iron metal

11. (a)State the modern periodic law

(b)Study the periodic table below then answer the questions that follow.

Write the formula of compounds formed when element

  1. U and W combine together
  2. Q and W combine together

Draw and write electronic configuration of Y.

12. (a)Catherine is planning to make fire for cooking ugali for her family. What are necessary conditions which must be present so that she can make fire successfully for cooking ugali for her family?

(b)Give a reason for each of the followings

  1. Water is universal solvent
  2. Some metal like zinc do not get rust.
  3. Chlorine gas is collected by downward delivery
  4. Carbon dioxide turns lime water into milky colour.

SECTION C (15 MARKS)

Answer only one (1) question.

13. (a)Give good reason (s) for the following. (Answer according to the question demand).

  1. Natural gas is so popular in heating and cooking in homes. (2 points)
  2. Nuclear energy is not a sustainable source of energy. (2 points)
  3. Coal and petroleum are non-renewable sources. (1 point)

(b) State the main raw materials and process involved in the manufacture of each of the following products.

  1. Wood charcoal
  2. Coke
  3. Lamp black
  4. Animal charcoal

14. (a) 25cm 3 of 0.1MHCl were neutralized by 23cm 3 of Na 2 CO 3 solution. Calculate the concentration of the alkali in grams per litre.

(b)Suggest a suitable indicator of each of the following titrations

  1. Hydrochloric acid against ammonia solution
  2. Sulphuric acid against sodium hydroxide solution
  3. Ethanedioic acid against potassium hydroxide solution

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 104

THE PRESIDENT’S OFFICE MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCY BASED SECONDARY EXAMINATION SERIES

CHEMISTRY-SEPT 2022

FORM THREE

032

Time:3 Hours SEPT, 2022

Instructions

  1. This paper consists of sections A, B and C with a total of fourteen (14)

questions.

  1. Answer all questions in sections A and B and one (1)question from section C.
  2. Sections A and C carry fifteen (15) marks each and section B carries seventy (70) marks.
  3. Cellular phones and any unauthorized materials are not allowed in the examination room.
  4. Write your name on every page of your answer sheets.
  5. The following constants may be used.

Atomic masses: H = 1, O = 16, C = 12, N = 14, Na = 23, Cl = 35.5, K = 39

Ca = 40

Avogadro’s number:

GMV at s.t.p =

1 Faraday = 96,500 coulombs.

Standard pressure = 760 mm Hg.

Standard temperature = 273 K.

1 litre ==

SECTION A (15 Marks)

Answerall questions in this section.

  1. For each of the items (i) – (x), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer sheet.
  1. A Bunsen burner is a chief source of heat in the laboratory that produces both blue and yellow flames. Which one among the following heat sources produce a blue flame:

A: spirit lampB:gas stoveC:kerosene stove

D:candleE:hurricane lamp

  1. “Water is referred to as the universal solvent.What does this statement mean?

A: it is commonly known liquid

B:it exists in all three states of matter

C:it dissolves more substances than any other known liquid.

D:it is used for cooking, drinking and washing bodies and clothes

E:it is colourless, odourless and tasteless liquid

  1. Kiraka was suffering from stomach pain for the whole day. Which material among the following could be used to relieve his pain?

A:dilute hydrochloric acid B: cucumber C:lemon

D:tamarind E:blueberries

  1. Electronegativity increases from left to right across the period in the periodic table. In which group and period does the most electronegative element belong?

A:group I period 3B:group VII period 2 C:group I period 7

D: group VII period 1E:group VII period 3

  1. During sunny days, the water in ponds dry completely leaves ponds barely. Which process takes place in that season?

A:condensationB:meltingC:evaporation

D:sublimationE:deposition

  1. The apparatus used to heat small amounts of solid substances within a gas jar is:

A:evaporating dishB:test tube holderC:deflagrating spoon

D:gas jarE:desiccator

  1. One of the following is a common component that causes reddish brown colour on some materials:

A:sodium metalB:alloyC:water vapour

D:oilE:grease

  1. Kileo visited the forest at their village, and fortunately, he found some water in the pond mixed with some dust particles. Which simple method among the following he used to get pure drinking water?

A:fractional distillationB:filtrationC:condensation

D:crystallizationE:simple distillation

  1. Ammonium ion reacts with sulphate ion to form a compound. The oxidation state of ammonium ion in that compound is:

A:+1B:4C:-1D:+4E:-2

  1. Asha boils the water from the well using electric kettle;but the heating process takes long time. The substance that causes this problem is:

A:aluminiumB:calciumC:sodium

D:potassiumE:both A and C

  1. Match the items from list A with the correct responses in list B by writing the letter of the correct response in your answer sheets.

List A

List B

  1. The radical with valence of three.
  2. The elements with both metallic and non-metallic properties.
  3. The most reactive element in the electrochemical series.
  4. It is formed by the contribution of electrons.
  5. The elements which are incredibly stable and rarely reactive.

A:Electrovalent compound

B:Potassium

C:Bromine

D:Covalent compound

E:Phosphate

F:Noble gases

G:Metalloids

SECTION B (70 Marks)

Answerall questions in this section

  1. Element X found in group II period 4 chemically interacted with element Y found in group VII period 3 forming compound Z.

(a)(i)Write the actual names of element X, Y and compound Z.

(ii)What is the chemical combination involved in this interaction?

(b)(i)Draw the structure of the compound Z

(ii)Give two properties of compound Z.

  1. (a) Air is a homogeneous mixture of different gases in the atmosphere. Give

three reasons to support this statement.

(b)With the help of balanced chemical equation, explain what will happen to:

(i)A piece of iron bar left to the exposure.

(ii)Anhydrous copper (II) sulphate when put into the watch glass and placed

on the laboratory bench.

  1. (a) (i) Why chemical symbols are very important to chemist? Give three reasons

(ii)Write the symbols of phosphorous, fluorine, manganese and copper.

(b)Why some elements are assigned symbols with only one letter while

Others bear with two letters?

  1. A certain compound was found to have the following composition by mass: 24.24% carbon, 4.04% hydrogen and 71.72% chlorine.
  1. What is the simplest formula of the compound formed?
  2. Calculate the percentage composition by mass of water in magnesium

Chloride hexahydrate.

  1. (a) (i) Give two reasons why laboratory exists are advised to open outward?

(ii)Why laboratory safety precaution is very important?

(b)Categorize the following laboratory compounds into corrosive and flammable:

Sodium hydroxide, spirit, sulphuric acid, oil, aro and benzene

  1. (a) Differentiate molar mass of a substance from molar volume of gases.
  1. The Golden Boy conducted an experiment for the production of oxygen gas

bythermal decomposition of potassium chlorate. If he used 20g of potassium

chlorate, what volume of oxygen would be produced at s.t.p?

  1. (a) Briefly state two importance of balancing chemical equations.
  1. Silver nitrate was introduced into dilute hydrochloric acid to form

products.

  1. Which type of chemical reaction took place?
  2. Write the net ionic equation for that reaction.
  1. (a) Give the names of the processes of making coke from coal and charcoal from

wood.

(b)(i)“Liquid fuel is more advantageous than solid fuel”. Give three points to

support this statement.

(ii)Write down the composition of water gas and producer gas.

  1. (a) A solution of sodium hydroxide was electrolysed using platinum electrodes.

Write the reactions which take place at the electrodes and give reason why

the solution becomes alkaline.

  1. What mass of zinc will be formed in electrolysis using a 15 amperes of

electricity for one and a half hours?

  1. Form three students at Tusomeni Secondary School performed an experiment for the neutralization of sodium hydroxide solution and hydrochloric acid. 25 of sodium hydroxide were exactly neutralized by 25 of 0.10M HCl.
  1. Calculate the concentration of sodium hydroxide in:
  1. mol/ (ii) g/
  1. What is the suitable indicator for:
  1. The above titration
  2. The titration of strong acid against strong base

SECTION C (15 Marks)

Answerone (1) question in this section.

  1. Cutting down trees for firewood and charcoal causes major catastrophic effects to the environment. Using four points analyse these effects and suggest two alternative ways that can be used to minimize the energy loss encountered.
  2. Water has a property of dissolving some minerals that affect it permanently; as a result, it becomes very disadvantageous to many rural people. As a young chemist and one among these people, explain the four effects of using this water and suggest two ways of removing the effect.

Page1 of5

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 96

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCE BASED SECONDARY EXAMINATION SERIES

CHEMISTRY TERMINAL EXAMINATION

FORM THREE-2022

Time: 3 Hours

Instructions.

  1.    This paper consists of section A, B and C with a total of 14 questions
  2.    Answer all questions in section A and and ONE (1) question from section C.
  3.    Section A and C carries 15 marks, while section B 70 marks
  4.    Cellular phones and any unauthorized materials are not allowed in the examination room.
  5.    Non programmable calculators may be used.
  6.    Write your number on every page of your answer booklet.
  7.    Where necessary the following constants may be used;

Atomic masses; H=1, C=12, N=14,O=16, Na=23, S,=32, Ca =40, Cl =35.5, Cu=64, Zn=65.

Avogadro’s number = 6.02 x 1023

GMV at s.t.p = 22.4dm3

1 faraday = 96,500 coulombs.

Standard temperature = 273K

Standard pressure = 760mmHg.

1 Litre = 1 dm3 = 1000cm3

 SECTION A ( 15 Marks)

Answer all questions in this section.

1. For each of the items (i)-(xv), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.

  1. Chemistry is a study of
  1.              The chemicals used in the laboratory
  2.               An experiment carries out in industries.
  3.               The composition , structure and properties of matter
  4.              All scientific processes.
  1. Hassan wants to grid the granules of a certain chemical to fine powder. The apparatus he will use include a.
  1.              Pestle and filter funnel
  2.               Round-bottomed flask and trough
  3.               Mortar and pestle.
  4.              Bunsen burner and filter paper.
  1. Which of the following is a physical change?
  1.              Milk left on the counter turns sour
  2.               Common salt dissolves complete in water
  3.               A forest fire burns all the trees
  4.              Fruits are fermented to produce wine
  1. When a substance is heated and change from solid directly to a vapor the process is called
  1.              Condensation
  2.               Dissolving
  3.               Sublimation
  4.              Melting
  1. Which of the following gases if mixed with Hydrogen produce a very hot flame of up to 3000oC.
  1.              Oxygen
  2.               Neon
  3.               Chlorine
  4.              Argon.

 

  1. An isotope of Cadmium has an atomic number of 48 and mass number of 112. This mean that the Cadmium atom has.
  1.              48 protons, 64 neutrons, 48 electrons
  2.               64 protons, 48 neutrons, 64 electrons
  3.               48 protons, 112 neutrons, 48 electrons
  4.              112 protons, 112 neutrons, 112 electrons
  1. The reaction between Silver nitrate and Sodium chloride to form Silver chloride and Sodium nitrate is an example of a ………………. Reaction.
  1.              Direct combination
  2.               Simple displacement
  3.               Double displacement
  4.              Decomposition.
  1. Which of the following pairs of oxide are gaseous at room temperature?
  1.              Carbon dioxide and copper (II) oxide
  2.               Sulphur dioxide and copper (II) oxide
  3.               Carbon dioxide and Sulphur dioxide
  4.              Copper (II) oxide and Iron (II) oxide
  1. Ammonium chloride reacts with sodium hydroxide solution on warming. The net ionic equation for the reaction is.
  1.              H+(aq) + OH-(aq) → H2O(l)
  2.               NH+(aq) + OH-(aq) → NH3(aq) + H2O(aq)
  3.               Na+(aq) + Cl-(aq) → NaCl(aq)
  4.              2NH4+(aq) + 2Cl-(aq) → NaCl(aq) + Cl(g) + H2(g)
  1. Which of the following is not a property of Hydrogen gas?
  1.              It support combustion
  2.               It is slightly soluble in water
  3.               It is less denser than air
  4.              It is colorless and odorless

 

2. The following are the matching items .Match the correct item in LIST B corresponding one from LIST A. Write the letter in answer sheet provided.

LIST A

LIST B

  1. Metalloids
  2. Periodicity
  3. Alkali metal
  4. Alkaline earth metals
  5. Transitional elements

 

  1.              The properties of elements are periodic function of their relative atomic masses.
  2.               The regular periodic changes of elements due to their atomic number.
  3.               The properties of an elements change systematically according to their atomic number.
  4.              The metallic elements in group I.
  5.               The metallic elements in group II.
  6.                Are the elements which element form colored compound.
  7.              The elements which tend to display both metallic and non-metallic characteristics.
  8.              The element in group VII
  9.                 Fluorine
  10.                 Sodium
  11.              The vertical column in the periodic table.
  12.               The horizontal column in the periodic table.
  13.             The elements which do not react to form compounds. 

 

 

SECTION B ( 70 Marks)

Answer all questions in this section.

  1.                a) i. What is an air?

    ii. Is air a compound or mixture? Give four (4) reasons to support your answer.

b) State the methods of separating the following mixture. Give a reason to support your answer.

  1. Kerosene and water
  2. Muddy water
  3. Ethanol and milk.
  1.                a). Define the following terms
  1. First Aid
  2. First aid kit.

b) Give five (5) items found in the First aid kit and their uses.

c) What First aid do you give to a person who has fainted?

  1.                a) Differentiate between the following terms.
  1. Chemical reaction and chemical equation.
  2. Reactants and products
  3. Displacement reaction and Double displacement reaction.

b) Complete and balance the following reaction.

  1.              +                   → Mg(NO3) (aq) + Zn(s)

 

  1. Pb(NO3)2 (s) + Na2SO4 (aq) 

 

  1. Pb(NO3)2 (s)         Heat

 

  1.                a) Explain the meaning of the following terms.
  1. Mole
  2. Molarity

b) i. State the Avogadro’s law.

ii. Mention two (2) applications of Avogadro law

  1.                a) By using a well labeled diagram explain the preparation of oxygen using hydrogen peroxide.

b) List three chemical properties of oxygen.

  1.                a) Name the following compounds according to the IUPAC system of nomenclature
  1. Fe2(SO4)3
  2. KMnO4
  3. H2SO4

b) What is fuel? 

c) State four (4) the characteristics of good fuel.

  1.                a) Define
  1. Atom
  2. Isotopes

b) i. What is an electronic configuration? 

ii. Give three (3) applications of electronic configuration.

  1.             a) Distinguish between the following terms
  1. Corrosive and irritant
  2. Radioactive and explosive
  3. Solution and suspension

b) i. What is flame?

ii. Differentiate between luminous and non-luminous flame. Give four (4) points. 

  1.            a) Explain the meaning of the following terms
  1. Empirical formula
  2. Molecular formula
  1.                The compound of carbon and hydrogen has the empirical formula CH3. Find its molecular formula if its relative molecular mass is 30 (r.a.m carbon = 12).

 

  1.            a) State four (4) natural sources of water.

b) Explain four (4) economic importance of water.

SECTION C (  15 Marks)

Answer one (1) question from this section.

 

  1.            a) Explain the meaning of  each of the following terms
  1. Concentration of the substance
  2. Molar mass
  3. Stoichiometry

b) Calculate the number of moles in each of the following substances

  1. 1.064g of Magnesium nitrate
  2. 1.397g of Copper (II) sulphates
  3. 3.67dm3 of Sulphur dioxide at s.t.p

c) Calculate the number of ions present in 30g of Aluminum sulphates.

14.  With the aid of a chemical equation, describe how you would prepare pure solid sodium chloride by the action of an acid and a base.

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 83

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCE BASED SECONDARY EXAMINATION SERIES

CHEMISTRY MID TERM EXAMINATION

FORM THREE-MARCH/APRIL-2022

Time: 3Hours

Instructions.

  1. This paper consists of section A, B and C with a total of 14 questions
  2. Answer all questions in section A and B and ONE (1) question from section C.
  3. Section A and C carries 15 marks, while section B 70 marks
  4. Cellular phones and any unauthorized materials are not allowed in the examination room.
  5. Non programmable calculators may be used.
  6. Write your number on every page of your answer booklet.
  7. Where necessary the following constants may be used;

Atomic masses; H=1, C=12, N=14,O=16, Na=23, S,=32, Ca =40, Cl =35.5, Cu=64, Zn=65.

Avogadro’s number = 6.02 x 1023

GMV at s.t.p = 22.4dm3

1 faraday = 96,500 coulombs.

Standard temperature = 273K

Standard pressure = 760mmHg.

1 Litre = 1 dm3 = 1000cm3

 SECTION A (15 Marks)

 Answer All questions in this section.

  1. For each of the items (i – x) choose the correct answer from among the given alternatives and write its letter in the table provided
    1.      Kinetic nature of matter describe
  1. The shape of three states of matter
  2. The movement of particles in the three state of matter
  3.  The process of treating solid, liquid and gas
  4. Describe the meaning of matter
  5. Make up of matter

 

  1.  Nitrogen (III) oxide has a formula
  1. N2 O5
  2. NO3
  3. NO2
  4. NO3
  5. N3O2

 

  1.                           A pair of the following substances from a miscible liquid
  1. Paraffin and water
  2. Paraffin and benzene
  3. Water and glycerin
  4. Water and kerosene
  5. Water and milk

 

     (vi)        Which one of the following sets of elements is arranged in order to increase  

            electro negativity starting with the least one?

  1. Chlorine, fluorine, nitrogen, oxygen, carbon
  2. Fluorine, chlorine, oxygen, nitrogen, carbon
  3. Carbon, nitrogen, oxygen, chlorine, fluorine
  4. Nitrogen, oxygen, chlorine, carbon, fluorine
  5. Nitrogen, oxygen,sodium, carbon, fluorine

 

  1. “Striking back” means
  1. Luminous flame
  2. Flame burning inside the barrel when the air hole is open
  3. Non-luminous flame
  4. Flame burning inside the barrel when the air hole is closed
  5. Excess gas
    1. Element Q of atomic number 15 is found in
  6. Group V and period 3
  7. Group I and period 2
  8. Group III and period 4
  9. Group IV and period 1
  10. Group 15 period 5

 

  1. Which of the following natural processes is not a chemical change?
  1. Photosynthesis
  2. Respiration
  3. Rain formation
  4. Corrosion of iron
  5. Souring of milk

 

  1.  This mixture of substances can extinguish fire
  1. Oxygen and nitrogen
  2. Carbon and sand
  3. Carbondioxide and hydrogen
  4. Carbondioxide and sand
  5. Hydrogen and oxygen

 

  1.   The physical test for oxygen is
  1. Support the burning splint
  2. Colourless, no smell and tasteless
  3. Produces “POP” sound
  4. Turns lime water blue
  5. Has sweet aroma

 

  1.        An element ‘A’ of element configuration 2:8:3 combines with an element ‘B’of configuration 2:6. The chemical formula of the compound is 
  1. B6 A3
  2. A3 B6
  3. A2 B3
  4. A3 B2
  5. B2A3

 

 

SECTION B.

  1.  Match the item in list A with the responses in list B by writing the letter of the correct response in list the box below.

List A.

  1. Octet state
  2. Fossil fuels
  3. Rusting of iron
  4. Desiccators
  5. Solvent extraction

      List B.

  1. Hardening of oil
  2. Aqueous
  3. Full of eight electrons in the outermost shell
  4. Water and kerosene
  5. Inert state
  6.  Electronic configuration
  7. Coal, natural gas
  8. Used to obtain oil from groundnuts
  9. Potassium, sodium
  10. Enzymes
  11. For drying substance
  12.  Condensation
  13. Ionic equation
  14. Catalyst
  15. Chemical change
  16. Physical change

 

 

 

SECTION B (70 Marks) 

Answer all questions in this section

  1.  (a) Define the following terms:
    1. Fuel ……………………………………………………………………………………………………………………………………………………
    2. Calorific value of a fuel ……………………………………………………………………………………………………………………………………………………
    3. Energy value of a fuel ……………………………………………………………………………………………………………………………………………………

(b) Give two examples of each of the following:

(i) Solid fuel ………………………………….., ……………………………..

(ii) Liquid fuel…………………………………..,……………………………...

(iii) Gaseous fuel ……………………………….., …………………………….

(c) Name four characteristics of a good fuel 

(i) ………………………………………………………………………………

(ii) ………………………………………………………………………………

(iii) ……………………………………………………………………………..

(iv) ……………………………………………………………………………..

 

  1. (a) Water is said to be a compound. Verify this statement
    1. …………………………………………………………………………
    2. ………………………………………………………………………….
    3. ………………………………………………………………………….
    4. ………………………………………………………………………….

 

(b) Study the apparatus arranged below and answers the questions below.

 

 

 

 

  1. Name the apparatus labeled
  1. ……………………………………………………………………
  2. ……………………………………………………………………
  3. …………………………………………………………………..

E…………………………………………………………………..

 

 

 

 

  1. What is the function of the apparatus labeled E? …………………………………………………………………………
  2. What is the role of manganese (IV) oxide (MnO2) in the above experiment? ………………………………………………………………………......
  3. How can you test the presence of oxygen …………………………………………………………………………..
  4. What was the aim of the above experiment? …………………………………………………………………………..
  5. Write a balance chemical equation of the reaction which occurred in apparatus C above …………………………………………………………………………

 

  1. (a) (i) Define valence ………………………………………………………………………………………………………………………………………………………………………………

(ii) Write down the valence of the following elements: 

Magnesium …………………………………. Lithium ……………………………

 

(iii) Name the following radicals and state their valences

 

Radical

Name

Valence

NH4+

 

 

CO 32 -

 

 

HCO3-

 

 

SO32

 

 

SO2  4-

 

 

NO 3-

 

 

 

(b) Write the following compounds 

(i) Aluminium oxide ………………………………………………………………

(ii) Lead (II) nitrate ……………………………………………………………..…

(iii) Ammonium carbonate …………………………………………………………

(iv) Lead (II) sulphide ……………………………………………………………..

(v) Copper (II) hydroxide …………………………………………………………

 

  1. (a) Define:
    1. Empirical formula ……………………………………………………………………………………………………………………………………………………
    2. Molecular formula ……………………………………………………………………………………………………………………………………………………

 

(b) A certain gaseous compound contains 82.8% of carbon and 17.2% of hydrogen by mass. The vapour density of the compound is 29. Calculate its molecular formula (C = 12, H = 1)

 

  1. (a) By giving one example define the following terms
    1. Suspension ……………………………………………………………………………………………………………………………………………………
    2. Electroplating ……………………………………………………………………………………………………………………………………………………
    3. Galvanizing ……………………………………………………………………………………………………………………………………………………
    4. Element …………………………………………………………………………………………………………………………………………………….
    5. Matter ……………………………………………………………………………………………………………………………………………………

 

(b) Give four uses of hydrogen gas 

(i) ……………………………………………………………………………….

(ii) ………………………………………………………………………………

(iii) ……………………………………………………………………………..

(iv) ……………………………………………………………………………..

 

  1. (a) What do you understand by the term isotope? ………………………………………………………………………………………………………………………………………………………………………………

(b) Chlorine has two isotopes of chlorine – 35 3517 Cl, which constitutes of 75% in the mixture and chlorine – 37 3717 Cl, which constitutes of 25%. Calculate the relative atomic mass of chlorine. 

 (c) One of the methods of preventing iron from rusting is sacrificial protection,   

                  why it is called so  ……………………………………………………………………………………………………………………………………………………………………………………

      9. (a) Give the meaning of the following terms 

     (i) Solution ……………………………………………………………………………..

     (ii) Emulsion …………………………………………………………………………… 

               ……………………………………………………………………………………

     (iii) Potable water ………………………………………………………………………

              …………………………………………………………………………………….

      (b) State the modern periodic table     

………………………………………………………………………………………………………………………………………………………………………………………………

        (c) Name heat sources used in the laboratory 

        (i) ………………………………………………………………………………

        (ii) ……………………………………………………………………………..

        (iii) ……………………………………………………………………………

        (iv) …………………………………………………………………………… 

 

     10. (a) Show how the following change in the periodic table:

      (i) Electronegativity ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

(ii) Ionization energy ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

 

(iii) Atomic size ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

 

(b) “Chemistry is the useless subject” Discuss the above statement with reasons

(i)……………………………………………………………………………………………      

     …………………………………………………………………………………………

(ii) …………………………………………………………………………………………..

     …………………………………………………………………………………………..

(iii) …………………………………………………………………………………………

      ………………………………………………………. ………………………………..

(iv) …………………………………………………………………………………………

      …………………………………………………………………………………………

 

11.      a) What is the hardness of water?

b)  Briefly explain types of hard of water.

c)   State the causes of hardness of water for each type mention in (b) above.

d)  Explain how you would remove the hardness of water according to its type.

e)  Give three (3) advantages and three (3) disadvantages of the hard water.

12.   Balance the following equations: 

  (i)Ca + H3PO4→ Ca3(PO4)2 + H2

  1.                      Cu + HNO3 → Cu (NO3 )2 + NO2 +H20
  2.                      SnCi2+FeC13→SnC14+FeCI

13.     Give the name of the types of reaction represented by each of the following chemical equations.

  1.                      C3H8(g) +50,(0)→ 3CO2 + 4H20(1)
  2.                      2Pb (N 03),(,)→2Pb0(,) + 4NO2 +02(g)

(iii)Zn(s)+CuS04(aq) —>ZnSO4(aq) +CU(S)

14.     Complete the following equations and determine the type of chemical reaction involved in each case.

(i) Zn(s)+ H2SO4(aq)

(i) AgN 03(aq) + NaCl(aq)

(iii) N2(g) + H2(g) 

 

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 74

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

SECONDARY EXAMINATION SERIES

CHEMISTRY    ANNUAL   EXAMINATION

FORM THREE-NOVEMBER 2021 

 

Instructions

  1.                This paper consists of sections A, B and C with a total of fourteen (14) questions.
  2.                Answer all questions in sections A and B and one (1) question from section C.
  3.                Sections A and C carry fifteen (15) marks each and section B carries seventy (70) marks.
  4.                Cellular phones and any unauthorised materials are not allowed in the examination room.
  5.                Write your Examination Number on every page of your answer booklet(s).
  6.                The following constants may be used.

 H 1,    C = 12,  0=16,    N = 14,  Cu = 64,   Pb = 108.

                  A vogadros number = 6.02 x 1023.

GMV at s.t.p = 22.4 dm3.

1 Faraday = 96,500 coulombs.

Standard pressure = 760 mm Hg.

Standard temperature = 273 K.

1 litre = 1 dm3 = 1000 cm3.


 

SECTION A (20 Marks) 

Answer all questions in this section.

1. For each of the items (i) (x), choose the correct answer from the given alternatives and write its letter beside the item number.

 (i) Which of the following is an agricultural chemical products made by the application of chemistry?

  1.              Drugs           
  2.              Pesticides        
  3.              Clothes 
  4.              Yeasts 
  5.               Cement.

 (ii) A current of 0.2 A was passed through an electrolyte for 16 minutes and 40 seconds. What is the quantity of electricity produced in coulombs?

  1.               2000 C  
  2.              1000 C 
  3.               200 C 
  4.               0.20 C 
  5.                7686 C.

(iii) Substance X liberates chlorine gas from acidified potassium chloride. The behaviour of X is described as:

  1.   an oxidising agent    
  2.   an oxidising and reducing agent
  3.   catalyst   
  4.   a reducing agent
  5.   bleaching agent.

(iv) Which carbonate is the most stable to heat?

  1.               Calcium carbonate   
  2.               Copper (II) carbonate
  3.               Lead (II) carbonate 
  4.               Zinc carbonate 
  5.               .Iron (II) carbonate.

(v)  Aluminium does not react with water and does not corrode much in air because

  1.               it is below hydrogen in the reactivity series
  2.               it forms a stable carbonate which prevents reactions
  3.               the metal is covered with a protective coating of an oxide 
  4.               aluminium ions have positive charges
  5.                it is very stable.

(vi) Which of the following compounds does NOT belong to the alkenes homologous series?

  1.               C2H4 
  2.               C3H6  
  3.               C4H 8 
  4.               C5H10 
  5.                C6H 14.

(vii) In the following equilibrium equation, 2S02(g) +O2(g) https://myfiles.space/user_files/30996_4958b541bbe404eb/1581488537_chem2018_files/image001.png 2S03 The forward reaction is exothermic. Which change would increase the production of sulphur trioxide at equilibrium?

  1.               Increasing temperature
  2.               Decreasing temperature
  3.               Decreasing sulphur trioxide concentration 
  4.              Decreasing pressure 
  5.               Adding a catalyst.

(viii) When a burning fuel produces blue color it means there is

  1.    adequate supply of oxygen with production of soot.
  2.     inadequate supply of oxygen without production of soot. 
  3.     inadequate supply of oxygen with production of soot.
  4.     adequate supply of oxygen with production of less heat.
  5.      adequate supply of oxygen with production of more heat.

(ix)  Which of the following equations represents the combustion of methane with the products collected at 120oC?

  1.               CH4(l) +2O2(g) →CO2(g) + 2H2O(l)
  2.               CH4(g) +2O2(l) →CO2(s) + 2H2O(l)
  3.               CH4(g) +2O2(g) →CO2(g) + 2H2O(g)
  4.               CH4(l) +2O2(l) →CO2(l) + 2H2O(g)
  5.                CH4(l) +2O2(g) →CO2(g) + 2H2O(g)

   (x) Which of these can be reduced when heated with carbon?

  1.               Aluminium  
  2.              Calcium carbonate
  3.              Iron (III) oxide 
  4.              Magnesium oxide 
  5.                Sodium oxide.

 


2.   Match the items in List A with the responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided. Match the items in List A with the responses in List B by writing the letter of the correct            

List A

List B

  1.  A gas with pungent choking smell and forms misty.
  2.   A compound used in domestic water - softening.
  3.  The hardest allotrope of carbon.
  4.  A gas which turns lime-water milky.
  5.  A substance which is amorphous form of carbon.
  1.               Carbon dioxide
  2.               Carboxylic acids
  3.               Iron (III) oxide
  4.               Nitrogen
  5.                Diamond
  6.                Sodium carbonate
  7.               Hydrogen chloride
  8.               Sulphur
  9.                  Graphite 
  10.                 Ethanol
  11.               Chlorine
  12.                Calcium
  13.             Ammonia gas
  14.               Plastic sulphur
  15.               Coke


SECTION B (70 Marks)

Answer all questions in this section.

3. (a) Define the following terms: 

  1. Neutralization.
  2. Unsaturated solution.
  3. Thermal decomposition.

(b) State three main physical properties of water and show the usefulness of each property.

(c)   State three industrial application of electrolysis.

 

4.   (a) Copper obtained from copper pyrites (CuFeS2) is impure for electrical wiring and has to be purified by electrolysis.

(i) Name the electrolyte and the electrodes used during electrolysis. 

(ii) Write the observations that can be made during the electrolysis.

(b) The following flow diagram shows the stages in the contact process

https://myfiles.space/user_files/30996_4958b541bbe404eb/1581488537_chem2018_files/image002.jpg

 (i)     Give the names of element A, catalyst B and an acid C.

 (ii)  Write  a balanced chemical equation for the formation of sulphur trioxide in stage 2

5. (a) Suggest one method of separating each of the following:

(i)             Green solution from leaves. 

(ii)      Alcohol from water.

 (b)   Elements K, L, M and N have atomic numbers 6, 8, 9 and 20 respectively. Classify each element into its respective period and group.

6.  (a) Give one example in each of the following:

 (i) Alkali earth metals.

(ii)  Noblegases .

(iii) Transition elements.

(b) Write the names of the following processes of changing matter from one state to another.

(i) Gas to liquid. 

(ii) Ga s to solid. 

(iii) Solid t o gas .

7 (a) Define the following:

   ( i ) Mole .

 ( i i ) Molarmass .

(b) 112 dm3 of oxygen gas was collected at s.t.p when a sample of lead nitrate was completely decomposed by heat. Calculate the volume of nitrogen dioxide gas produced.

8. (a)   Identify and state the environmental problem caused by the gas which is released from the blast furnace in the extraction of iron from its oxide.

(b)  The following equation shows the reaction between hydrogen and iodine gas to form hydrogen iodide gas,H2(g)  + I2(g)  ↔ 2HI (g) ∆H= -800Kj/mol.                   Giving a reason, explain what would happen to the position of equilibrium if 

(i) temperature is lowered.

(ii) hydrogen iodide gas is pumped into the system.

9.  (a) Name two elements which are expected to show similar chemical reaction with magnesium. What is the basis for your choice?

(b) State the main raw material and the process involved in the manufacture of the following products.

  1. Wood charcoal
  2. Coke
  3. Lampblack.

 

(c) (i) Name the compound which causes temporary hardness of water and the compound which causes permanent hardness of water.

(ii) Write one balanced chemical equation in each case to show how to remove temporary and permanent hardness of water.

10. (a) Suggest one best method for separating each of the following mixtures:

(i)  Common salt and water

(ii) Iodine and sand.

(iii) Pieces of iron and sand.

 (b) Carbon dioxide can be prepared by adding an acid to calcium carbonate.

(i) Using a named acid, write a balanced chemical equation for the reaction. (ii) Name all the products formed in (b) (i).

 11 . ( a ) With the aid of a chemical equation, describe how you would prepare pure solid sodium chloride by the action of an acid and a base.

  (b) (i) Why petroleum and coal are non-renewable sources of energy?

(ii) Give three alternatives to non-renewable sources of energy. 

 12. Three moles of nitrogen gas combine with five moles of hydrogen gas to form ammonium gas by Haber process.

  1.                 Which reactant is present in smaller amount?
  2.                 Calculate the grams of the reactant left in the container.
  3.                 How many moles of NH3 are produced?
  4.                 How many litres of NH3 are produced at STP?

 


SECTION C (15 Marks)

Answer one (1) question in this section.

13.(a) Give three advantages of using chemical equations over word equations.

(b) You are provided with a compound composed of 22.2% zinc, 11.6% sulphur, 22.3% oxygen, and the rest percentage is water of crystallization. Calculate the molecular formula of the compound if its molecular mass is 283.

14. Explain six measures for minimizing the environmental degradation caused by extraction of metals in Tanzania.

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 70

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCE BASED SECONDARY EXAMINATION SERIES

CHEMISTRY 1MID TERMEXAMINATION

FORM THREE-AUGUST/SEPT-2021

Time: 3Hours

Instructions.

  1.              This paper consists of section A, B and C with a total of 14 questions
  2.              Answer all questions in section A and B and ONE (1) question from section C.
  3.              Section A and C carries 15 marks, while section B 70 marks
  4.              Cellular phones and any unauthorized materials are not allowed in the examination room.
  5.              Non programmable calculators may be used.
  6.              Write your number on every page of your answer booklet.
  7.              Where necessary the following constants may be used;

Atomic masses; H=1, C=12, N=14,O=16, Na=23, S,=32, Ca =40, Cl =35.5, Cu=64, Zn=65.

Avogadro’s number = 6.02 x 1023

GMV at s.t.p = 22.4dm3

1 faraday = 96,500 coulombs.

Standard temperature = 273K

Standard pressure = 760mmHg.

1 Litre = 1 dm3 = 1000cm3

SECTION A (15 Marks)

Answer All questions in this section.

1. For each of the items (i)-(xv), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.

(i)Why oxygen differs from other gases?

  1. It neither burns nor support combustion.
  2. It supports combustion but does not burn.
  3. It burns but does not support combustion.
  4. It burns and supports combustion.
  5. It explodes and support combustion.

(ii)  Why is hydrogen gas collected over water and by upward delivery method?

  1. It is insoluble in water and less denser than air.
  2. It is soluble in water and denser than air.
  3. It is insoluble in water and denser than air.
  4. It is soluble in water and less denser than air.
  5. It is soluble in both water and air.

(iii) The following are the uses of chromatography except:

  1. to analyse blood in crime scenes.
  2. to detect different fibres.
  3. to detect water pollution.
  4. to bleach dye/colour.
  5. to test purity of organic substances.

(iv) Which statement is the most correct about chemistry laboratory?

  1. Is a special room designed for conducting chemical tests.
  2. Is a special room designed for science practicals.
  3. Is a special room designed for keeping apparatuses. 
  4. Is a special room where data analysis is carried out.
  5. Is a special room where students learn chemistry.

(v) Which carbonate is the most stable to heat?

  1.   Calcium carbonate   
  2.   Copper (II) carbonate
  3.   Lead (II) carbonate 
  4.   Zinc carbonate 
  5.   .Iron (II) carbonate.

(vi) In the following equilibrium equation, 2S02(g) +O2(g) 2S03 The forward reaction is exothermic. Which change would increase the production of sulphur trioxide at equilibrium?

  1.                      Increasing temperature
  2.                      Decreasing temperature
  3.                      Decreasing sulphur trioxide concentration 
  4.                     Decreasing pressure 
  5.                      Adding a catalyst.


   (vii) Which of these can be reduced when heated with carbon?

  1.  Aluminium  
  2. Calcium carbonate
  3. Iron (III) oxide 
  4. Magnesium oxide 
  5.  Sodium oxide.


(viii)   Which of the following is the electronic configuration of an element Y found in period 3 and group II of the periodic table?

  1.  2:8 
  2.  2:8:2    
  3.  2:6
  4. 2:8:8:2   
  5. 2:8:4 


(ix) Which of the following is NOT among the composition of air?

  1. Noble gases 
  2. Carbon dioxide 
  3. Nitrogen 
  4. Hydrogen 
  5. Water vapour.

(x)  If a stead current of 2 amperes was passed through an aqueous solution of iron (II) sulphate for 15 minutes, then the mass of iron deposited at the cathode will be:

  1. 54 g.
  2. 56 g.
  3. 0.54 g.
  4. 28 g.
  5. 0.52 g.


2.  Match the items in List A which the responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided.

LIST A

LIST B

  1. Its nitrate decomposes to the metal, nitrogen dioxide and oxygen. 
  2. Its chloride is used as a drying agent for most gases.
  3. Its carbonate is used to remove hardness of water.
  4. Has maximum valency of five.
  5. Burn with a lilac color flame.
  1. Copper
  2. Sodium
  3. Potassium
  4. Calcium
  5. Phosphorous
  6. Silver
  7. lead

SECTION B (70 Marks)

Answer all questions in this section.


3. An atom of element X having atomic number 11 combines with an atom of element Y haying atomic number 9 to form a compound.

(a) Write the formula of the compound and state the type of bond formed in the compound.


(b) Give four properties of the compound formed in 7(a).            (7 marks)

(b)

  • Soluble in water
  • High melting and boiling point
  • Contact electricity in molten state
  • Consists of ionic structure.

4. Explain how to handle chemicals having the warning signs of flammable, corrosive, harmful, explosive and toxic in the laboratory.

5.   (a) Copper obtained from copper pyrites (CuFeS2) is impure for electrical wiring and has to be purified by electrolysis.

(i) Name the electrolyte and the electrodes used during electrolysis. 

(ii) Write the observations that can be made during the electrolysis.

(b) The following flow diagram shows the stages in the contact process 

 (i)     Give the names of element A, catalyst B and an acid C.

 (ii)  Write  a balanced chemical equation for the formation of sulphur trioxide in stage 2

6. (a) Copper can be obtained from the ore, copper pyrites (CuFeS2). The ore is heated in a limited amount of air giving the following reaction:

 4CuFeS2 + 11O 2 ? 4Cu + 2Fe 2 O 3 + 8SO2 .

(i) Calculate the maximum mass of copper that can be obtained from 367 kg of copper pyrites.

(ii) State why the gaseous product from this reaction must not be allowed to escape into the atmosphere.

(b)   State three industrial application of electrolysis.

7. A student attempted to prepare hydrogen gas by reacting zinc metal with dilute sulphuric acid. In this experiment zinc metal granules of about 0.5 cm diameter and 0.20 moles of acid were used.

The rate of formation of hydrogen gas was found to be slow.

(a)Explain three ways in which the rate of formation of hydrogen gas could be increased.

(b)If the student wanted 36 cm3  of hydrogen gas at s.t.p, what amount of the acid would be required.


8.  (a) 20 cm3 of a solution containing 7 g dm-3 of sodium hydroxide were exactly neutralized by 25 cm3 of 0.10 M hydrochloric acid. Calculate the concentration of sodium hydroxide in moles per dm3.

(b)  Give two examples in each of the following solution.

(i)  Gaseous solution.

(ii) Solid solution.

9. The flow chart in Figure 3 shows the process of obtaining a sample of nitrogen gas. Study it and answer the questions that follow.

(a) Identify X (I mark)

(b) Write an equation for the reaction with heated copper turnings. (1 mark)

(c) Name an impurity in the sample of nitrogen gas. ( I mark)


10. (a) Name two ores in which sodium occurs.

(b) During extraction of sodium using the down's process, calcium chloride is added to the ore. Give a reason for the addition of calcium chloride. (1 mark)

(c) State two uses of sodium. ( I mark)

11. Figure 3 shows the apparatus used to burn hydrogen in air. Use it to answer the questions that follow.

https://www.advance-africa.com/images/burnhydrogen.png

State the role of substance X.

(ii) Give the name of the substance that could be used as X. (1 mark)

(iii) State the role of the suction pump. (1 mark)

(iv) Name the product Y formed. (1 mark)

(v) Give a simple physical test to prove the identity of Y. (1 mark)

(vi) State the difference between 'dry' and 'anhydrous'. (2 marks)

12. (a) Consider elements with atomic number 1, 11, 12 and 17.

(i) What are the types of oxides formed by elements with atomic number 11 and 12?

(ii)  Write an equation which represents a reaction between the element with atomic number 1 and 17.

(iii) Write a balanced chemical equation between the oxide of the element with atomic number 11 and aqueous solution of the compound formed in 4 (a) (ii).


 (b) Suggest one method for the separation of each of the following:

(i) Iodine and sand.

(ii) Green solution from leaves.

(iii) Alcohol and water.

(iv)  Iron fillings and powdered calcium carbonate.


SECTION C (15 Marks)

Answer one (1) question in this section.

13.  25 cm3 of 0.1 M HCl were neutralized by 23 cm3 of sodium hydroxide solution. Calculate the concentration of the alkali in grams per litre.


14. Describe four common stages for the extraction of metals. Does the extraction of gold follow all four stages? Give reasons.

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 58

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCE BASED SECONDARY EXAMINATION SERIES

CHEMISTRY 1TERMINALEXAMINATION

FORM THREE-2021

Time: 3Hours

Instructions.

  1.            This paper consists of section A, B and C with a total of 14 questions
  2.            Answer all questions in section A and B and ONE (1) question from section C.
  3.            Section A and C carries 15 marks, while section B 70 marks
  4.            Cellular phones and any unauthorized materials are not allowed in the examination room.
  5.            Non programmable calculators may be used.
  6.            Write your number on every page of your answer booklet.
  7.            Where necessary the following constants may be used;

Atomic masses; H=1, C=12, N=14,O=16, Na=23, S,=32, Ca =40, Cl =35.5, Cu=64, Zn=65.

Avogadro’s number = 6.02 x 1023

GMV at s.t.p = 22.4dm3

1 faraday = 96,500 coulombs.

Standard temperature = 273K

Standard pressure = 760mmHg.

1 Litre = 1 dm3 = 1000cm3

 SECTION A (20 Marks)

 Answer All questions in this section.

1. For each of the items (i)-(xv), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.

  1. 1.4 g of potassium hydroxide is dissolved in water to form 250 cm3 of solution. What is the molarity of this solution?
  1.  0.01 M
  2.  0.1 M
  3.  1.4 M
  4.  5.6 M
  5.  6.0 M
  1. In the blast furnace carbon monoxide is prepared by passing carbon dioxide over a red­hot coke. Carbon dioxide is
  1.  an accelerator
  2.  an oxidizing agent
  3.  a reducing agent
  4.  a catalyst
  5.  oxidized.
  1.                     A catalyst can be described as a substance 
  1. that alters the rate of reaction
  2.  that slows down the rate of reaction
  3.  used in every reaction so as to speed up rate of reaction
  4.  that starts and speeds up the rate of reaction
  5.  that terminates chemical reaction.

 (iv) A covalent bond is formed when

  1.  a metal combines with a non­metal
  2.  potassium and oxygen combine
  3.  ammonia is formed
  4.  two metals combine
  5.  atom looses an electron.

 (v) A solvent can be obtained from a solution by

  1.  evaporation followed by decantation
  2.  filtration and condensation
  3.  evaporation and filtration
  4.  evaporation and condensation
  5.  crystallization followed by sublimation.

 (vi) Aqueous sugar solution is a poor conductor of electricity because

  1.  water and sugar are covalent compounds
  2.  water is a non­electrolyte
  3.  sugar is a non­electrolyte
  4.  sugar is covalent when in liquid form
  5.  sugar dissolves completely in water.

 (vii)  In order to produce the greatest amount of hydrogen in a short time, one gram of magnesium ribbon should react with

  1. 10 cm3 of 0.5 M sulphuric acid
  2. 40 cm3 of 0.5 M acetic acid solution
  3. 40 cm3 of 0.5 M sulphuric acid solution
  4. 20 cm3 of 1 M sulphuric acid solution
  5. 20 cm3 of 1 M acetic acid solution.

 (viii)  Fractional distillation process of a mixture of water and ethanol is possible because

  1. water and ethanol have the same boiling point
  2. water has lower boiling point than ethanol
  3. ethanol has lower boiling point than water
  4. water and ethanol form partially immiscible liquid solution
  5. water and ethanol are immiscible liquids.

 (ix)  Which of the following substances represent a group of acidic oxides?

  1. Carbon dioxide, carbon monoxide and sulphur dioxide
  2. Sulphur trioxide, nitrogen dioxide and nnitrogen monoxide
  3. Carbon dioxide, sulphur dioxide and dinitrogen oxide
  4. Sulphur trioxide, carbon dioxide and nitrogen dioxide
  5. Carbon monoxide, nitrogen oxide and sulphur dioxide.
     

 (x)  What will the molarity of a solution which contains 26.5 g of anhydrous sodium carbonate in 5 dm3 of solution?

  1. 0.05 M
  2. 0.25 M
  3. 5.30 M
  4. 0.025 M
  5. 0.50 M

2. Match the items in LIST A with the responses in LISTB by writing the letter of the correct response beside the item number in the answer booklet provided.

LIST A

LIST B

  1. A gas that explodes when flame is applied in presence of air.
  2. An element with atomic number 40.
  3.                     A gas prepared in laboratory by isolation of air.
  4.                      An element with electronic configuration of 2:8
  5. An element used in making jewelers.
  1. Mercury
  2. Diamond
  3. Hydrogen
  4. Zinc
  5. Sodium
  6. Calcium.
  7. Neon
  8. Argon
  9. Nitrogen.

SECTION B (70 Marks)

Answer all questions in this section.

3. Hydrogen has can be prepared by passing steam over heated magnesium ribbon as shown in the figure 2.

https://www.advance-africa.com/images/hydrogengas.png

(a) Write an equation for the reaction that produces hydrogen gas. 

(b) Explain why the delivery tube must be removed from beneath the water before heating is stopped. 

(c) Explain why sodium metal is not suitable for this experiment. 

4. A solution contains 40.3g of substance XOH per litre .250.0cm3of this solution required 30.0cm3 of 0.3M sulphuric(VI)acid for complete neutralisation.

(a) Calculate the number of moles of XOH that reacted. 

(b) Determine the relative atomic mass of X. 

5. (a) Explain the following observations:

(i) The colour of aqueous copper(ii) sulphate fades when a piece of magnesium metal is dropped into the solution. 

(ii) A piece of iron bar is coated with a brown substance when left in the open on a rainy day. 

6. A mass of 1.24g of a divalent metal was deposited when a current of 6A was passed through a solution of a metal sulphate for 12 minutes.Determine the relative atomic mass of the metal( Faraday = 96,500 C mol-1

(d) State two application s of electrolysis. 


7. 30.0 cm3 of aqueous sodium hydroxide containing 8.0 g per litre of sodium hydroxide were completely neutralised by 0.294 g of a dibasic acid. Determine the relative formula mass of the dibasic acid. (Na = 23.0 ; O = 16.0 ; H 1.0) 

8(a). Using iron filings, describe an experiment that can be conducted to show that oxygen is present in air. 

(b)  Element U has atomic number 12 while element V has atomic number 16. How do the melting points of their oxides compare? Explain. (3 marks)

9. (a) Name two ores of iron. 

(b) Describe how the amount of iron in a sample of iron(III) oxide can be determined.

10.(a) Give three advantages of using chemical equations over word equations.

(b) You are provided with a compound composed of 22.2% zinc, 11.6% sulphur, 22.3% oxygen, and the rest percentage is water of crystallization. Calculate the molecular formula of the compound if its molecular mass is 283.

11.(a) (i) Name the compound which causes temporary hardness of water and the compound which causes permanent hardness of water.

(ii) Write one balanced chemical equation in each case to show how to remove temporary and permanent hardness of water.

(b) State four steps employed in the extraction of moderate reactive metals.

12.(a) Giving three reasons, explain why air is said to be a mixture of gases.

 (b) (i) People suffering from heart burn usually use wood ashes for relief. Mention characteristic which makes the ashes to be used for heart burn relief.

 (ii)Give four compounds found in laboratories which show the same characteristics as ashes.


SECTION C (15 Marks)

Answer one (1) question in this section.


13. Describe four common stages for the extraction of metals. Does the extraction of gold follow all four stages? Give reasons.

14. Read the following information carefully then answer questions that follow: 25 cm3 of potassium hydroxide were placed in a flask and a few drops of phenolphthalein indicator were added. Dilute hydrochloric acid was added until the indicator changed colour. It was found that 21 cm3 of acid were used.

(b) (i) What piece of apparatus should be used to measure out accurately 25 cm3 of sodium hydroxide solution?

(ii) What colour was the solution in the flask at the start of the titration?

(iii) What colour did it turn when the alkali had been neutralized? 

(c) (i) Was the acid more concentrated or less concentrated than the alkali? Give reasons for your answer.

(ii) Name the salt formed in the neutralization.

(iii) Write an equation for the reaction. 

(d) Utilizing the given information describe how you can obtain pure crystals of the salt. 

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 50

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

SECONDARY EXAMINATION SERIES

CHEMISTRY 1 MID TERM EXAMINATION

FORM THREE-2021

 

Time: 3Hours

Instructions.

  1. This paper consists of section A, B and C with a total of 14 questions
  2. Answer all questions in section A and and ONE (1) question from section C.
  3. Section A and C carries 15 marks, while section B 70 marks 
  4. Cellular phones and any unauthorized materials are not allowed in the examination room.
  5. Non programmable calculators may be used.
  6. Write your number on every page of your answer booklet.
  7. Where necessary the following constants may be used;

Atomic masses; H=1, C=12, N=14,O=16, Na=23, S,=32, Ca =40, Cl =35.5, Cu=64, Zn=65.

Avogadro’s number = 6.02 x 1023

GMV at s.t.p = 22.4dm3

1 faraday = 96,500 coulombs.

Standard temperature = 273K

Standard pressure = 760mmHg.

1 Litre = 1 dm3 = 1000cm3

                       SECTION A (20 Marks)

                       Answer All questions in this section.

1. For each of the items (i)-(xv), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.

  1. The region around the nucleus of an atom where electrons are found is called:-
  1. Shell (orbits or energy levels)
  2. Solar or Lunar eclipse                                
  3. Ozone layer
  4. Outer most shell.
  1. The following is a chemical property of oxygen.
  1. It burns completely when exposed and produce a “pop sound”.
  2. It supports combustion .                            
  3. It produces unpleasant smell
  4. It reacts with vapour to form carbon dioxide gas.
  1. _________ is one of the use of hydrogen 
  1. it is used by mountain climbers
  2. it is used in painting
  3. it is used in manufacturing of ammonia       
  4. it is used for breathing.
  1. A special catalyst used in the laboratory preparation of oxygen gas by using potassium chlorate (KClO3) is:-
  1. Manganese (IV) oxide
  2. Zinc granules                                                 
  3. Anhydrous copper (II) sulphate
  4. Gas jar
  1. Which of the following chemical species have the same number of electrons?
  1. Cl, Be and O2-
  2. K+, Ca2+, Cl-  
  3. O2-, Ca2+ and  Ar                                     
  4. Na+, Mg2+, Be2+ and Li.
  1. Match each item in list A with response in list B by writing its correct letter to the number of the corresponding item in the table provided below.

 

LIST A

LIST B

  1. Chemical test for oxygen
  2. A substance which alters the rate of chemical reaction but itself remains chemically not changed at the end of the reaction.
  3. Atoms can neither be created nor destroyed
  4. Forces holding the opposite charged ions
  5. Combining capacity of element
  1. Ionic bond 
  2. Ionic equation
  3. Chemical composition
  4. Potassium chlorate (KClO3)
  5. Catalyst
  6. Dalton’s atomic theory
  7. Three (3) sub atomic particles called protons, neutrons and electrons.
  8. Valence
  9. It produces a “pop sound” when a burning splint is dipped in a gas jar containing it.
  10. It re- lights a wooden glowing splint. 

 

QN

I

II

III

IV

V

ANSWER

 

 

 

 

 

 

SECTION C (70 MARKS)

  1. (a) use the following information about elements  P,Q,R,S and T shown in the table below to answer the questions that follows.

Element 

Atomic number

Atomic mass

P

8

16

Q

9

19

R

11

23

S

6

12

T

18

40

           Questions:-

  1. Write down the electronic configuration of elements: P,Q,R,S       and T.

Element

P

Q

R

S

Electronic configuration

 

 

 

 

 

  1. How many neutrons are present in element T?

______________________________________________________________________________________________________________________

 

 

(b) Write the chemical symbols for the following elements:-

(i) Magnesium________ (ii) Tin _______(iii) chromine_____    (iv) Lead______

 

(c ) For each of the following chemical symbols of elements write its corresponding chemical name:-

  1. Si______________        (ii) Cu____________       (iii) Mn_____________
  1. The figure below is part of the periodic table which includes  the first 20 elements. Study it carefully and answer the question that follows.

 

 

 

 

1

 

18

2

5

 

8

10

12

14

16

19

3

6

 

9

11

13

15

17

20

4

7

Transitional elements

 

 

 

 

 

 

 

Questions:-

 For each number write the chemical symbol of the corresponding element

Number

1

2

4

6

8

11

12

17

Symbol 

 

 

 

 

 

 

 

 

 

  1. Write the formula which represents a compound formed between an element with atomic number 1 and element with atomic number 17. ___________
  2. Considering the elements with atomic number 12 and 17, which is a metal and which is a non – metal?

Atomic number

Comment

12

 

17

 

  1. Write the number which represent an element with a property of burning in oxygen to form waters________________________
  2. Write the number which represent and element with inert property._________

 

  1. (a) Define the following
  1. Empirical formula
  2. Molecular formula 

(b) 0.7g of nitrogen combines with 1.6g of oxygen to form a nitrogen oxide. Given the molecular mass of a compound is 92.

Calculate: (i) The empirical formula

       (ii)The molecular formula

            (Use atomic masses  N= 14, O= 16). 

  1.  (a) (i) What is water?______________________________________________

              (ii Write a chemical formula for water_______________

  1. Outline three (3) uses of water ________________________________________________________________________________________________________________________________________________________________________

(b) (i) What is a fuel?_____________________________________________

(ii) Give two examples for each of the following categories of fuels in terms of their states of matter

Solid fuels_____________________________________________________

Liquid fuels_____________________________________________________

Gaseous fuels__________________________________________________

 

6. (a) Define the term a chemical equation. 

(b) Write down components of a chemical equations list only three (3). 

(c) Balancing the following chemical equations;

  1. Al(NO3)3(aq) + 3NaOH(aq)                      Al(OH)3(s) + NaNO3(aq) 
  2. Ba(NO3)2(aq) + (NH4)2SO4(aq)                   BaSO4(s) + NH4NO3(aq)
  3. CaCl2(aq) + Na2CO3(aq)                      NaCl(aq) + CaCO3(s) 
  4. Zn(NO3)2(aq) + Na2S(aq)                    NaNO3(aq) + ZnS(s)  
  5. Na2CO3(aq) + HNO3(aq)                    NaNO3(aq) + H2O(l) + CO2(g)

7. (a) Give the IUPAC names for each of the following compounds:-

  1. Cu2O______________________(ii)Na2SO4_________________________________
  2. Fe2O3__________________________

(b) Calculate the oxidation number of underlined elements:-

(i) CO2-            (ii) HCO3                                          (iii) KClO3

 

(c) Write the electronic configuration of Cl-  and hence draw its electronic diagram.

8. Explain the meaning of each of the following types of chemical reactions and support your explanation with the help of a relevant chemical equation.

  1. Synthesis (combination) reaction
  2. Decomposition reaction
  3. Precipitation reaction
  4. Single displacement reaction
  5. Neutralization reaction 
  1. Soap solution of different amount of water are tested from four different sources and produces lather observed for 30 seconds. The three groups of waster were the untreated; boiled and treated by ion exchange. The results are as follows;

 

Sample 

Volume of soap (cm3) used for water that was

Untreated

Boiled

Passed through ion exchanger

A

B

C

D

12

17

26

1.6

1.8

17

20

1.6

1.8

1.7

1.8

1.6

 

                Use the above results to answer the following questions; 

  1. Which is the hardest water sample? Why? 
  2. Which sample is like distilled water? Explain. 
  3. Which chemical substance might be the cause of hardness in (i) Sample A   (ii) Sample B? 
  4. Write an equation for the reaction of removing hardness in sample C. 

10. (i) Define the following terms;

  1. Soft water 
  2. Hard water 
  3. Permanent hardness of water 
  4. Temporary hardness of water 

(ii) Explain why the ability of temporary hard water to conduct electricity falls when the water is boiled but does not fall when temporary hardness is removed by addition of washing soda.

 11. Give a brief account to the following 

  1. Why does water note have any effect on litmus paper?
  2. (i) What would happen to a well stoppered   bottle full of water left in a deep freezer over the night? Why does this happen?

(ii) Why is iron not usually recommended in the construction of steam pipes and boilers.

  1. (i)  Name two compounds which may cause temporary hardness of water and two   ions which largely cause permanent hardness of water.

      (ii) Write one balanced chemical equation which shows how temporary hardness can be removed by boiling. Also write  one balanced equation which shows how sodium carbonate can be used to remove permanent hardness of water.

12. (a) Define the following words:-

  1. Deliquescence
  2. Efflorescence

(b) Give at least three (3) uses of salts

(c ) When zinc granules and dilute sulphuric acid are reacted together, gas M is produced. The gas produced is collected by downward displacement of water. Use this information to answer the questions below:-

  1. Name the gas M
  2. How is gas M tested?
  3. Why is a the gas collected by down ward displacement of water?

 

SECTION C (15 Marks)

Answer one question in this section.

 

13. For each of the following write equations for the reactions that would take place.

  1. Action of heat on Sodium nitrate, Lead (II) nitrate and mercury (II) Nitrate.
  2. Action of heat on sodium carbonate and copper (II) Carbonate.

14.  (a) 416g of anhydrous barium chloride where obtained when 488g of hydrated salt were heated. 

       Calculate the value of n is the formula BaCl2.nH2O (Ba = 137)

 

(b) Give the meaning of the following;

       (i) An acid

      (ii) Molar solution of an acid 

     (iii) Give three characteristics of acid. 

 

 

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 49

PRESIDENT'S OFFICE 
REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT 
ANNUAL EXAMINATION 
CHEMISTRY F3- FORM THREE

NAME………………………………………..CLASS……………………………TIME: 3HRS

Instructions:

  1. This paper consists of sections A, B and C with a total of fourteen (14) questions.
  2. Answer all questions in sections A and B and one (1) question from section C.
  3. Cellular phones and any unauthorized materials are not allowed in the examination room.
  4. Write your Examination Number on every page of your answer booklet(s)
  5. The following constants may be used;

H = 1, C = 12, N = 14, O = 16, Na = 23, Pb = 207 

Al = 27, Cu = 64, Ca = 40, Cl = 35.5, Mg = 24. 

Avogadros number = 6.02 x 1023

GMU at stp = 22.4dm

Faradays constant = 96500C 

Standard pressure = 760 mm Hg 

Standard temperature = 273K. 

SECTION A (15 Marks)

Answer all questions in this section.

  1. From each of item (i) – (x) choose the correct answer from among the given alternatives and write its letter beside the item number.
  1. How many moles of sodium carbonate are present in 200cm3 of a 2M solution of the salt?
  1. 0.4 Mol      B. 0.01 Mol    C. 0.5 Mol     D. 10 Mol
  1. The chemical properties of an element is determined by;
  1. Mass number
  2. Mass spectrometer
  3. Number of neutrons
  4. Number and arrangement of electrons
  1. A solution can be define as a;
  1. Uniform mixture of two substance
  2. Heterogenous mixture of solute and solvent
  3. Homogenous mixture of solute and solvent
  4. Uniform mixture of two insoluble substance.
  1. An ion of element Y has 2:8: 8++ as its electronic configuration. The number of proton is the atom of y is;
  1. 18    B. 16    C. 40    D. 20
  1. Which of the following chemical can be used to prepare oxygen without applying heat?
  1. Hydrogen peroxide
  2. Potassium chlorate
  3. magnesium oxide
  4. Zinc carbonate
  1. Calcium and magnesium are members of  group of element in the periodic table called;
  1. Alkali earth metals
  2. Alkali metals
  3. Transition metals
  4. Amphoteric metals
  1. In the electrolysis of CUSO4 the weight of copper plate out of the cathode by a current of 0.70 Amps flowing for 10 minutes is;
  1. 0.139gm     B. 10.48gm    C. 14.48gm    D. 1.148gm
  1. In the reaction;

2FeCl2 +     Cl2                          2FeCl3

Chlorine may be regarded as; 

  1. A reducing agent
  2. An oxidizing agent
  3. A catalyst
  4. Halogens
  1. When 0.125 Faraday of electrolysis are passed through a copper (II) Sulphate soln. The mass of copper deposited will be;
  1. 4g    B. 8g     C. 64g    D. 32g
  1. The percentage of water of crystallization in MgSO4.7H20 is;
  1. 53.4%      B. 51.2%    C. 49.2%    D. 47.3%
  1. Match the item in list A with their responses in List B by writing the letter of the correct response against the item number;

LIST A

LIST B

  1. A homogeneous mixture of two or more substance.
  1. Is a liquid metal.
  1. Ionization energy
  1. Is a method of extracting oil from nuts.
  1. Simplest formula
  1. Antibiotic solution
  2. Existence of element in different physical form of the same state.
  3. A group of atoms acting as a single substance.
  4. Have both acidic and basic properties.
  5. Shows different colours in acidic and alkaline medium.
  6. The energy required to remove and electron from the influence of the nucleus of the atom.
  7. Bonding
  8. Solution
  9. Suspension
  10. Mercury
  11. Copper
  12. Solvent extraction
  13. Empirical formula
  14. Molecular formula

SECTION B (70 Marks)

Answer all questions in this section.

  1. (a) Differentiate between;
  1. Atomic number and Atomic mass
  2. Distillation and sublimation

(b) Define the following terms;

  1. Molar solution
  2. Ion
  3. Molar mass
  4. Neutralization
  1. (a) How many electrons will be needed to discharge 0.135g Aluminium?

(b) A solution of acetic acid (CH3COOH) was made by dissolving 3.00g of the acid in 0.5 

dm3 of solution. Upon titration 12.00cm3 of this solution required 25.00cm3 of 

sodium hydrogen carbonate for complete neutralization. Calculate the molarity of the 

bicarbonate (NaHCO3).

The ratio of the reacting moles is 1:1.

  1. (a) Give the name of substance or apparatus which fits the following descriptions;
  1. It is used for measuring fixed volume of liquid
  2. It is used for holding and keeping apparatus up right.
  3. It is used as a drying agent.

(b)Write down three differences between potassium ions and potassium atom. 

  1. Carefully study the electronic configuration of the following element;
  1. : 2 : 4     B. : 2 : 7    C. : 2 : 8     D. : 2 : 8 : 2  

E. 2 : 8 : 8 : 2F = 2 : 8 : 6 

(a)Which of the above elements would you expect to be; 

  1. Metallic
  2. Non metallic
  3. Inert gases

(b)What would you expect to be the formula of the compound formed in each of the following pairs; 

  1. A with B
  2. B with E
  3. D with F

(c)Deduce the period and group in the periodic table of; 

(i)E(ii) F 

(d)Write down a balanced chemical equation showing what would happen if an oxide of element E was treated with dilute hydrochloric acid. 

  1. (a) Differentiate between water treatment and water purification.

(b) Mention three methods of purifying domestic water. 

(c) What causes the following; 

i. Temporary hardness in water 

ii. Permanent hardness in water 

(d) i. With the aid of chemical equations explain why it is possible to soften temporary 

hardness by boiling.

ii. Mention one advantages of using hard water. 

  1. (a) State Faraday laws of electrolysis.

(b) An element Z has a relative atomic mass of 88. When a current of 0.5 amperes was 

passed through fused chloride of Z for 32 minutes and 10 seconds 0.44 of Z were 

deposited at the cathode; 

  1. Calculate the number of Faradays needed to liberate one mole of Z.
  2. Write the formula of the  Z ions
  3. Write the formula of hydroxide of Z. 
  1. (a) What is the meaning of the following terms;
  1. Exothermic reactions
  2. Endothermic reactions

(b) Draw the energy – level diagram for exothermic reactions and Endothermic reactions. 

(c) Name four (4) characteristics of good fuel. 

  1. 20cm3 of solution containing 7g/dm3 of metal hydroxide XOH, were exactly neutralized by 25cm3 of 25 cm3 of 0.10M hydrochloric acid.

(a)Write a balanced chemical equation for neutralization of metal hydroxide XOH.

(b) Calculate the concentration of metal XOH in mole per dm3

(c)i. Calculate molar mass of XOH 

ii. Identify element X. 

  1. (a) i. List down three (3) factors affecting the selection of ion discharge at the electrode.

ii. Define the term electrolyte. 

(b) A bluish copper sulphate aqueous solution was electrolysed by using copper 

electrodes. 

  1. Write ionic chemical equations for the reactions which occurred at the cathode and anode.
  2. Explain what will happen to blue colour of copper sulphate solution as electrolysis continues.

(a) Define and point of titration

(b) What colour change indicate end point in the titration of a base against an acid on using (i) Methyl orange?(ii) Phenolphthalein?

(c) A teacher of chemistry provided his F3 students with the following:

AA – A solution of 0.12 0M HCl 

BB – A solution of hydrated sodium carbonate, Na2CO3 containing 14.30g/dm3. On titration by using a 20cm3 pipette one of the best student obtained the following readings from a standard burette 

Burette readings

Pilot

1

2

3

4

Final volume (cm3)

18.00

35.90

27.90

45.50

27.60

Initial volume (cm3)

0.00

18.00

10.20

27.90

10.00

Volumeused (cm3)

(i)Suggest the colour change at the end point 

(ii)Suggest the indicator used by the student in the titration

(iii)Complete the table above

(iv)Calculate the average volume used for complete neutralization of the base by acid

(v)Find the value of X in the formula Na2CO3X H2O

12.(a) State three main physical properties of water and show the usefulness of each property.

(b)State three industrial application of electrolysis.

SECTION C (15 Marks)

Answer one (1) question from this section.

12. Explain how to handle chemicals having the warning signs of flammable, corrosive, harmful, explosive and toxic in the laboratory.

13. Explain six measures for minimizing the environmental degradation caused by extraction of metals in Tanzania.

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 35


THE PRESIDENT'S OFFICE

MINISTRY OF REGIONAL GOVERNMENT AND LOCAL GOVERNMENT

AUGUST-SEPTEMBER   EXAMINATION SERIES

CHEMISTRY  FORM-3

2020

TIME: 2:30 HRS

 

Instructions

  1. This paper consists of sections A, B and C with a total of fourteen (14) questions.
  2. Answer all questions in sections A and B and one (1) question from section C.
  3. Cellular phones and any unauthorised materials are not allowed in the examination room.
  4. Write your Examination Number on every page of your answer booklet(s).
  5. The following constants may be used.

Atomic masses: H 1, O- 16, N- 14, S = 32, Zn - 65, Cl -35.5, cu - 64.

Avogadros number= 6.02 x 1023 image

GMV at s.t.p =22.4 dm3 .

1 Faraday= 96,500 coulombs.

Standard pressure = 760 mm Hg. Standard temperature 273 K.

1 litre =1 dm3 =1000 cm 3.

SECTION A (15 Marks)

Answer all questions in this section.

1. For each of the items (i) — (x), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.

(i) "Water is referred to as the universal solvent". What does this mean? 

  1. Water is neither acidic nor basic as compared to other liquids.
  2. Water exists in three states of matter than any other liquids.
  3. Water dissolves both organic and inorganic solutes. 
  4. Water is used more domestically than any other liquids.
  5. Water dissolves more substances than any other known liquids.

(ii)  What is the proper set of apparatus would you use to grind granules of a solid substance into fine powder in the laboratory?

  1. Pestle and filter funnel   
  2. Separating funnel and mortar
  3. Pestle and filter paper                  
  4. Pestle and mortar
  5. Thistle funnel and mortar

 

(iii)  Which of the following sets of processes uses a gas that ignites with a "pop" sound when a lighted splint is passed through it?

  1. Balloon filling, welding and diving 
  2. Hardening oil, balloon filling and welding
  3. Hardening oil, balloon filling and diving
  4. Fueling rocket, diving and welding
  5. Balloon filling, fueling rocket and diving

 

 (iv) A current of 0.2 A was passed through an electrolyte for 16 minutes and 40 seconds. What is the quantity of electricity produced in coulombs?

  1.  2000 C  
  2. 1000 C 
  3.  200 C 
  4.  0.20 C 
  5.  7686 C.

(v)  Aluminium does not react with water and does not corrode much in air because

  1.  it is below hydrogen in the reactivity series
  2.  it forms a stable carbonate which prevents reactions
  3.  the metal is covered with a protective coating of an oxide 
  4.  aluminium ions have positive charges
  5.  it is very stable.

 

(vi) When a burning fuel produces blue color it means there is

  1. adequate supply of oxygen with production of soot.
  2. inadequate supply of oxygen without production of soot. 
  3. inadequate supply of oxygen with production of soot.
  4.  adequate supply of oxygen with production of less heat.
  5.  adequate supply of oxygen with production of more heat.

 

 (vii) Which of these can be reduced when heated with carbon?

  1.  Aluminium  
  2. Calcium carbonate
  3. Iron (III) oxide 
  4. Magnesium oxide 
  5.  Sodium oxide.

(viii) Which of the following is NOT among the composition of air?

  1. Noble gases 
  2. Carbon dioxide 
  3. Nitrogen 
  4. Hydrogen 
  5. Water vapour.

 

(ix) If a steady current of 2 amperes was passed through an aqueous solution of iron (II) sulphate for 15 minutes, the mass of iron deposited at the cathode will be.

  1. 30g.
  2. 56g.
  3. 0.54g.
  4. 28g.
  5. 0.52g.

 

(x) Two substances are allotropes of carbon if

  1. Both reduce heated iron (II) oxide to iron
  2. Have different crystalline structure
  3. Have equal masses
  4. Have equal shape
  5. Have the same arrangement of atoms

2. Match the descriptions in List A with the corresponding scientific procedures in List B by writing the letter of the correct response besides the item number in the answer booklet provided.

LIST 1

LIST B

  1. A statement of how the results relate to hypothesis.
  2. A series of investigations.
  3. A statement that identifies an event, fact or situation.
  4. A tentative explanation.
  5. A step in which the researcher explains the results.
  1. Conclusion
  2. Data analysis
  3. Data collection
  4. Experimentation
  5. Hypothesis
  6. Observation
  7. Problem identification

 

SECTION B (70 Marks)

Answer all questions in this section.

3. (a) How many chlorine molecules are in 20 cm of chlorine gas at s.t.p? 

   (b)Calculate the number of ions present in 5 g of copper II nitrate. 

4.  (a) Distinguish temporary hardness from permanent hardness of water.

 (b) With the help of chemical equations, explain how you can remove each type of water hardness in 5(a).

5.   (a) Copper obtained from copper pyrites (CuFeS2) is impure for electrical wiring and has to be purified by electrolysis.

(i) Name the electrolyte and the electrodes used during electrolysis. 

(ii) Write the observations that can be made during the electrolysis.

(b) The following flow diagram shows the stages in the contact process image

 (i)     Give the names of element A, catalyst B and an acid C.

 (ii)  Write  a balanced chemical equation for the formation of sulphur trioxide in stage 2

 

6.  (a) Give one example in each of the following:

 (i) Alkali earth metals.

(ii)  Noblegases .

(iii) Transition elements.

(b) Write the names of the following processes of changing matter from one state to another.

(i) Gas to liquid. 

(ii) Ga s to solid. 

(iii) Solid t o gas .

7. (a) State four steps employed in the extraction of moderate reactive metals.

(b) Write balanced chemical equations to show how chlorine reacts with the following:

  1. water.
  2. aqueous iron (II) chloride solution.
  3. hydrogen sulphide.

 

8. (a) State three main physical properties of water and show the usefulness of each property.

(b)   State three industrial application of electrolysis.

9. (a)An atom M has an atomic number 14 and mass number 28. 

(i)What is the number of protons and neutrons?

 (ii) Write the electronic configuration of atom M.

(b) Calculate the volume of water which was produced when 1,120 cm3 of oxygen at s.t.p. was liberated during the decomposition of hydrogen peroxide. The density of water = 1.0 g/cm3 

 

10. (a) Determine the empirical formula of a substance that has the following composition by mass; 49.5% oxygen.

(b) Give one reason why Alluminium is chosen to make each of the following items:

  1. Cooking foil
  2. Overhead electric cables
  3. Window frames

 

11. (a) Identify and state the environmental problem caused by the gas which is released from the blast furnace in the extraction of iron from its oxide.

(b) (i) Draw a labeled diagram of a simple electrolytic cell which show how copper is purified.

(ii) Write balanced ionic equations to show the electrode reactions which occur when copper is purified.

12. (a) (i) Why chemistry laboratory exits open outward?

 (ii) State the uses of any four items found in a First Aid Kit.

(b)  (i) Arrange the following metals in order of increasing reactivity; zinc, magnesium, calcium, copper and mercury.

 (ii) Which one of the metals in (b) (i) above reacts with steam to form an oxide which is white when cold and yellow when hot?

 

SECTION C (15 Marks)

Answer one (1) question from this section.

13. In Tanzania, soil conservation is very important for Industrial Materials production. Explain six methods that are used to manage loss of plant nutrients from the soil.

14. 0.48g of a metal, M was placed in a test tube and hot copper (II) sulphate solution was added to it and stirred until the reaction stopped. The metal (M) displaced copper from copper (II) sulphate solution. Copper was filtered, washed with water, dried at 1000 C  and the mass found to be 1.27g. Given that, the balanced chemical reaction that occurred is M (s)  + CuSO  4(aq)  imageMSO  4(aq)  + Cu  (s) 

(a) Calculate;

  1. The number of moles of copper that were formed and the number of moles of M that were used in the reaction.
  2. The relative atomic mass of M and hence identify metal M.

(b) State the appearance of the metal formed (Cu).

(c) With ionic equations, explain why the reaction can be considered to involve both oxidation and reduction.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 24

THE PRESIDENT’S OFFICE MINISTRY OF EDUCATION, LOCAL ADMINISTRATION AND LOCAL GOVERNMENT

CHEMISTRY- TERMINAL EXAMINATION-MAY

FORM THREE

TIME: 2HRS                                                                                           2020

NAME:_______________________________________CLASS:___________

INSTRUCTIONS

  1. This paper consists of 3 sections A, B,and C
  2. Answer all questions in all sections
  3. Phones and electronic calculators are not allowed
  4. All work should be done using blue or black pen
  5. The following information and constants may be useful

H=1, N=14, O=16, C=12, Fe=56, Pb=207, Cl=35.5, Ca=40, Mn=55, K=39, 1litre=1dm3=1000cm3

Avogadro’s constant=6.02x1023 particles

1 faraday=96500 coulombs

GMV at STP=22.4dm3

SECTION A (20 MARKS)

1. For each item (i-x) choose the correct answer from given alternative and write it beside the item number in answer booklet provided.

(i) An element in periodic table with atom number 18 belongs to which of the following

  1. Group 1 and period 1
  2. Group O and period III
  3. Group III and period III
  4. Group V and period IV
  5. Group VII and period IV

(ii) The ionic equation when ammonium chloride react with sodium hydroxide is

  1. 2NH+4(aq) + 2Cl- image 2NH3 + Cl2 + H
  2. NH+4 +  OH- image NH3  + H2O
  3. Na+   + Cl- image      NaCl
  4. 2NH+4      + 2Cl-(aq) image 2NH3(g) + 2Hcl(g)
  5. H+   + OH- image H2O

(iii) The reason why white anhydrous copperII sulphate turns Blue when exposed to atmosphere is

  1. Reacts with carbon dioxide
  2. Reacts with oxygen
  3. Becomes dry
  4. Absorbs water vapour
  5. Decomposes

 (iv) Chemical change means

  1. Change in reversible
  2. Can easily be separated
  3. Change is complete
  4. Produces no change in mass
  5. New substance is produced

 (v) If a stead current of 2 amperes was passed through an aqueous solution of ironII sulphate for 15 minutes, then, mass of iron deposited will be.

  1. 54g
  2. 56g
  3. 0.54g
  4. 28g
  5. 0.52g

 (vi) Which of the following solutions is the most concentrated?

  1. 50g of calcium carbonate in 100cm3 of water
  2. 60g of sodium chloride in 200cm3 of water
  3. 65g of potassium nitrate in 100cm3 of water
  4. 120g of potassium suphate in 200cm3 of water
  5. 50g of sodium hydroxide in 200cm3 of water

 (vii) Copper can be separated from mixture of zinc and copper by adding to the mixture

  1. Concentrated sulphuric acid
  2. Dilute sulphuric acid
  3. Aqueous solution of ZnSO4
  4. Catalyst
  5. Concentrated nitric acid

 (viii) 10cm of 0.4M sodium hydroxide are added to 40cm3 of 0.2M Hcl. The resulting mixture will be

  1. Neutral
  2. Alkaline
  3. Dilute
  4. Acidic
  5. Amphoteric

 (ix) The only metal which does not react with dilute Hcl is

  1. Magnesium
  2. Alluminium
  3. Copper
  4. Zinc
  5. Sodium

(x) During electrolysis of molten aluminum oxide; 3 faradays were needed to deposit one mole of aluminum. The number of electrons of aluminum will be:

  1. 6.02 X 1023
  2. 1.806 X 1023
  3. 18.06 X 1023
  4. 180.6 X 1023
  5. 1806 X 1023

2. Match the items in list A with responses in list B by writing the letter of correct response beside item number in separate answer sheet.

LIST A

LIST B

(i) Its nitrate decomposes to metal, nitrogen dioxide and oxygen

(ii) Its chloride is used as a drying agent

(iii) Its carbonate is used to remove hardness of water

(iv) It is stored paraffin

(v) It hydride ion is metallic in nature

(vi) Exists into two main physical forms

(vii) Greenish- yellow gas

(viii) Forms insoluble sulphate

(ix) Reacts with carbon dioxide to form an oxide

(x) Used as sacrificial element in catholic protection

  1. Potassium
  2. Zinc
  3. Argon
  4. Calcium
  5. Magnesium
  6. Chlorine
  7. Carbon
  8. Load
  9. Nitrogen
  10. Beryllium
  11. Neon
  12. Hydrogen
  13. Helium
  14. Sodium
  15. Boron
  16. Iodine
  17. Manganese
  18. Phosphorus
  19. silver

SECTION B (54 MARKS)

3. a) Why do chemistry laboratory exits open outward? 

State uses of any four items in first Aid Kit

b) i) Arrange the following metals in order of increasing reactivity – zinc, magnesium, calcium, copper, mercury

ii) Which of the following metals b (i) reacts with steam forming an oxide which is white when cold and yellow when hot?

4. a)20cm of solution containing 7g dm3 sodium hydroxide were exactly neutralized by 25cm of 0.1M Hcl. Calculate the concentration of sodium hydroxide in moles per dm

b) Give two examples of

(i) Gaseous solution

(ii) Solid solution

5. a)The table below show part of periodic table study it and answer questions that follow

H

 

He

Li

Be

B

 

 

 

F

 

 

 

Al

Si

P

S

Cl

Ar

 Fill all missing elements

(i) Write the reaction equation involved in industrial manufacture of sulphuric acid in contact process; starting with sulphur metal

(ii) Explain why sulphur trioxide is not dissolved directly in water to obtain sulphuric acid

6. a)Explain how you can separate crystals of copper II sulphate from pieces of broken glasses

b) With aid of equation explain how washing soda removes hardness of water

7. Table below give information about composition of three samples of water Mineral content per Mg per litre

Ions Kahama Maswa Bukombe
Ca2+ 28 82 18
Mg2+ 14 41 13
Cl- 53 7 22
Na+ 7 143 39
HCO-3 281 5 93
SO42-  2 14 16

(i) State two ways in which these ions get into water

(ii) Give two reasons, state hardest water sample

(iii) State two ways that can be used to remove hardness in (II)

b) Write the following molecular equation to ionic

(i) Fe(s) + CUSO4(aq)  → FeSO4(aq)    + Cu(s)

(ii) Na2SO4(aq)  + Bacl2(aq) → BaSO4(g)   + 2Nacl(aq)

State the type of chemical reaction

(8) a) When a burning splint is introduced in gas for containing CO2, the flame goes off.

i) What two properties of CO2 does this experiment lustrate?

ii) What type of equipment widely used in everyday life makes use of these two properties?

b) The equation below show dissociation of calcium carbonate 

CaCO3(s)    → CaO(s) + CO2(g)   H

(i) Is the forward reaction endothermic or exothermic?

(ii) What factors favour forward reaction?

(iii) What will be the effect on proportion of CaCO3 in the equilibrium mixture if temperature is decreased?

9. a)Lead nitrate decompose on heating as follows

2 Pb (NO3)2(g)   →     2PbO(S) + 4NO2 (g) + O2(g)

112dm3 of O2 were collected at STP when a sample of a lead nitrate was completely decomposed on heating. Calculate mass of load II nitrate in the sample.

b) Define the following terms

(i) Mole

(ii) Titrant

(iii) Analyte

(iv) Molar solution

10. a)Differentiate between

(i) A base and alkali

(ii) Atom and isotope

b) An organic compound P consists of 52.2% carbon, 13% hydrogen, and 34.8% oxygen.

The vapour density of P is 23. Calculate the molecular formula of compound P

11. Describe the extraction of iron using the blast furnace

SECTION C   (26 MARKS)

12. Assume that you are a chemist in a chemical plant and want to produce 100litres of chlorine gas per hour so as to reach company goal of producing 2400litres every day. What current of electricity will you allow to flow per hour?

13. A solution of hydrated sodium carbonate was nitrated with 1.68M nitric acid solution. 30cm3 of the solution required 28.75cm3 of nitric acid for complete reaction. If the solution was prepared by dissolving 12.056g of the carbonate to make 600cm3 of solution, determine the molecules of water of crystallization in hydrated sodium carbonate.

END

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 13

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION AND LOCAL GOVERNMENT

MID TERM EXAMINATION-MARCH 2020

CHEMISTRY FORM THREE

NAME………………………………….………………..CLASS…………………………….……………TIME: 3HRS

INSTRUCTIONS:-

1.This paper consists of sections A,B and C

2.Answer all questions in all sections

3.Whenever necessary, the following constructs may be used.

  • Atomic masses : O= 16, Na= 23, S=32,H=1, K=39, Al= 27,
  • GMV  at STP = 22.4dm3
  • Avogadro’s constant = 6.02 x 1023
  • 1litre = 1dm3= 1000cm3.

 

SECTION A (15  marks)

  1. Write the  letter of the correct answer in the answer sheet (s) provided for each of the following questions (i)  to (x).
  2. All domestic utensils made of iron undergo rusting when exposed to:-
  3. Air and fire
  4. Air and oil
  5. Air and water
  6. Water and oil
  7. When a small amount of common salt is dissolved in a glass of water the mixture formed is:-
  8. Heterogeneous
  9. Homogenous
  10. Immiscible
  11. Suspension 
  12. A chemist should acquire all of the following skills EXCEPT:-
  13. Experimentation
  14. Observation
  15. Problem identification 
  16. Surgery 
  17. An important property of oxygen which distinguishes it from other gases is that it:-
  18. Burns and supports combustion
  19. Burns but does not support combustion 
  20. Neither burns nor support combustion
  21. Support combustion but does not  burn
  22. The process of chlorination in water treatment aims at:-
  23. Forming suspension
  24. Killing micro- organisms
  25. Making syrup
  26. Removing bad odour

 

 

  1. One of the following is not correct about coke being a better fuel than coal as it:-
  2. Does not produce carbon dioxide gas
  3. Does not produce poisonous gas
  4. Has a higher heat content
  5. Is clean and smokeless
  6. Class E fire can best be extinguished by using:-
  7. Carbon dioxide
  8. Fire blanket
  9. Sand
  10. Water
  11. The following is a set of apparati which are used for heating:-
  12. Crucible, test tube, evaporating dish
  13. Evaporating dish, tongs, crucible
  14. Test tube, evaporating dish, tongs
  15. Tongs, crucible, test tube.
  16. Which of the following methods can be used to get oil from cotton seeds?
  17. Decantation
  18. Distillation
  19. Grinding and distillation
  20. Grinding followed by squeezing 
  21. Which of the following apparati is suitable for measuring volumes of smaller quantities of liquids?
  22. Beaker
  23. Burette
  24. Conical flask
  25. Measuring cylinder
  26. Match each item in list A with response in list B by writing its correct letter to the number of corresponding item in the answer sheet(s) provided.

LIST A

LIST B

  1. Chemical equation
  2. Contain H+ as the only positive ions
  3. Freezes at 00C and boils at 1000c
  4. Deliquescent
  5. X2+ + 2 e-           X
  1. Oxidation reaction
  2. Summary of many words in chemistry
  3. Reduction reaction
  4. Representation of reactants and products in a chemical reaction
  5. It turns lime water milky
  6. Acid
  7. Base
  8. Turns brown on exposure to air
  9. Water
  10. Compound which absorb water vapour from the atmosphere and form solution.

 

SECTION B (70 marks)

  1. (a) Define the term “neutralization reaction” (give one example)

(b) Write down the names and formulae of three common acids in the laboratory.

(c ) What is an indicator? Give four (4) examples of acid- base indicators.

(d) Write down the products formed when each of following pairs of compounds react:

(i)        Acid and metal

(ii)       Acid and metal carbonate

  1. (a) Complete and balance the molecular equations for the following reactions:-

 (b) Write a balanced chemical equation and its corresponding ionic equation for the reaction between dilute sulphuric acid and:-

  1. Sodium  hydroxide solution.
  2. Zinc granules.

N.B.  show all the state symbols.

             

  1. (a) Define the terms  (i) Mole   (ii) Molar mass

(b) Calculate the molar mass of  (i) Al(SO4)3   (ii) Na2 CO3 10H2O

( c) State the Avogadro’s law

(d) How many oxygen molecules are there in 20cm3 of oxygen gas at STP?

  1. (a) (i) Name any four heat sources in the chemistry laboratory

     (ii) Name two types of flames produced by the Bunsen burner

    (iii)How do the two above mentioned flames differ?

(b) Write down four (4) careers that are a result of studying chemistry.

  1. The diagram below represents the laboratory preparation of oxygen, study the diagram and then answer the questions  which follow:-

 

 

 

 

 

 

  1. (i) Label the parts indicated with letters A, B, C, D in the diagram

              (ii)     Does Oxygen burn? Why?

  1. The formula of manganese (iv) oxide is MnO2  and that of hydrogen peroxide is H2O2. Which compound produces oxygen?
  2. (i) What is the name of the method of collection the gas?

(ii) Explain the meaning of catalyst.

             (iii)How can you test for oxygen?

  1. Study the following part of the periodic table and then answer the questions that follows.

Note: The letters used are not the scientific symbols for the elements concerned.

 

  I                                                                                                                                  O

 

II

III

IV

V

VI

VII

 

 

 

 

 

 

 

N

 

 

K

 

 

 

Q

 

P

L

 

 

 

 

 

 

 

 

  1. Identify and write down the electronic configuration for the elements K,N,P and L
  2. What type of bond will exist in a compound formed when Q combines with L? write the chemical formula for the compound formed and list two chemical properties of the compound formed.

 

9.  (a) Write the chemical symbols for beryllium, boron, neon, nitrogen and phosphorus.

      (b) Why some of the elements in 9(a) are assigned symbols with only one letter while others bear symbols with two letters?

10. (a) Give three advantages of using chemical equations over word equations.

(b) You are provided with a compound composed of 22.2% zinc, 11.6% sulphur, 22.3% oxygen, and the rest percentage is water of crystallization. Calculate the molecular formula of the compound if its molecular mass is 283

11. (a) Which ways are the fossil fuels detrimental to the environment? Give four points.

 

     (b) Briefly explain how biogas is produced by using domestic waste.

 

12. (a) Write the IUPAC names of the following compounds 

  1. NaClO3 
  2. K1O3 
  3. NaH
  4. Ca(NO3
  5. NO

 

(b) Write the chemical formula of the following compounds 

(i) Lead (II) chloride 

(ii) Aluminium hydride 

(iii) Sodium hydrogen phosphate (v) 

(iv) Sulphur oxide (VI)

(v) Ammonium chloride

 

SECTION C (15 Marks)

 

Answer one (1) question from this section.

13. (a) Differentiate between basic salt and acidic salt.                                                

 (b) Categorize the following salts; 

       i.  PbSO4    ii.  MgHSO4     iii. Zn(OH)Cl   iv. MgHCO3  

         v. NH4HSO4     vi. Ba(NO3)2 

Salts 

Category 

 

 

 

(c) 1.16g of magnesium was allowed to react with excess dilute sulphuric acid. What 

      volume of Hydrogen gas at STP was liberated.                                            

14. (a) Define the following;

  1. Molarity 
  2. Standard solution 
  3. Equivalent point of titration 
  4. End point                                                                                                                 

 (b) On titration 20cm3 of a solution containing 2.65g per 500cm3 of A2CO3, exactly 

react with 20cm3 of 0.1M hydrochloric acid solution. Write balanced equation; 

  1. Molarity of A2CO                                                                                                  
  2. Molar mass of A2CO3                                                                                                                                                                    
  3. Atomic mass of A                                                                                                    
  4. Identify element A                                                                                                  

 

 

 

LEARNINGHUBTZ.CO.TZFORM THREE CHEMISTRY EXAM SERIES 3

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