CHEMISTRY FORM FOUR REGIONAL EXAMS (MOCK, PRE-NATIONAL, etc.)

THE UNITED REPUBLIC OF TANZANIA PRESIDENT'S OFFICE, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

ZONAL FORM FOUR MOCK EXAMINATION
(KATAVI, MBEYA, NJOMBE, RUKWA AND SONGWE REGIONS)

CHEMISTRY

Time 3:00 Hours Year: 2022

INSTRUCTIONS

  1. This paper consists of Section A, B and C with a total of fourteen (14) questions
  2. Answer all questions in Section 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 (s0
  5. The following constants may be used.
  • Atomic masses: H=1, O=16, N=14, S=32, Zn=65, Cl=35.5, Cu=63.5, Ag=108
  • Avogadro’s number = 6.02 x 1023
  • GMV at s.t.p. = 22.4dm3
  • 1 Faraday = 96,500 coulombs
  • 1 Litre = 1dm3 = 1000 cm3

SECTION A: (15 MARKS)

Answer all question in this section.

1. For each of the items (i) – (x), choose the correct answer from the alternatives and write its letter beside the item in the answer sheet provided.

(i) The best chemical warning signs that should be put on bottles containing kerosene is ……….

  1. Corrosive
  2. Toxic
  3. Flammable
  4. Explosive
  5. Harmful

(ii) A juice from Bakhresa Company written “shake well before use”. What does it mean?

  1. Suspension
  2. Solution
  3. Solute
  4. Emulsion
  5. Solvent

(iii) Alcohol reacts with carboxylic acid to form a group of organic compounds called

  1. Alkynes
  2. Halo alkane
  3. Esters
  4. Alkane
  5. Ethers

(iv) Ammonia gas is collected by which method among the following?

  1. Downwards displacement of water
  2. Upward delivery
  3. Downward delivery
  4. Upward displacement of air
  5. Collected over water

(v) Microelements from the soil are required by plants for their proper growth and development. The term microelements means ………

  1. The elements are very small
  2. The elements are required in small amount
  3. The elements are very rarely found in the soil
  4. The elements are not required by adult plants
  5. The elements are required by adult plants.

(vi) What is the oxidation number of the phosphorus in the following compound H3PO4?

  1. -5
  2. 0
  3. +2
  4. +5
  5. -3

(vii) What volume of hydrogen gas will be produced when 1.3g of zinc granules react completely with excess dilute sulphuric acid at s.t.p?

  1. 223cm3
  2. 130cm3
  3. 220cm3
  4. 440cm3
  5. 448cm3

(viii) Naima was preparing some food for her family using cooking oil in a frying pan. Accidentally the tipped over and a huge fire spread over her kitchen floor. Which extinguishers should be appropriate for putting off the fire?

  1. Wet sand carbon dioxide
  2. Dry powder and carbon dioxide
  3. Sand and wet chemicals
  4. We sand dry powder.

(ix) Which of the following is not organic compound?

  1. CO
  2. C6H12O6
  3. CH4
  4. CH3COOH
  5. C2H5Br

(x) The following reaction 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O (l) is an example of a

  1. Redox reaction
  2. Combination reaction
  3. Esterification
  4. Neutralization reaction
  5. Decomposition reaction.

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

LIST A

LIST B

  1. Atoms of the same element that contain different number of neutrons
  2. Sub-atomic particles not found in the nucleus of an atom
  3. The number of protons in the nucleus of an atom
  4. The total number of protons and neutrons in the nucleus of an atom
  5. Sub-atomic particle found in the nucleus of an atom.
  1. Electrons
  2. Isobars
  3. Protons
  4. Isotopes
  5. Nuclear
  6. Atomic mass
  7. Radical
  8. Atomic number

SECTION B: (70 MARKS)

Answer all questions in this section

3. (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 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.

4. (a) 25cm3 of 0.1MHCl were neutralized by 23cm3 of Na2CO3 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

5. (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.

6. (a)What do you understand the term chemical equation?

(b)Write ionic equation for the following chemical reactions.

  1. Milk of magnesia is used to relieve indigestion
  2. A divalent metal displacing monovalent metal from its soluble nitrate

7. (a)Define the following

  1. Soil fertility
  2. Leaching

(b)Briefly explain how soil PH is important? (Give three points)

(c)List four methods of fertilizer application.

8. The table below shows brads of bottled water for drinking and the concentration of different minerals ions in each brand. Study the table and then answer questions below it.

Composition In mg/litre

Mineral

Na+

Ca2+

Mg2+

Cl-

NO3-

SO42-

Fe2+

F-

UHAI

40.0

3.05

4.15

14.18

0.48

10.0

0

1.76

DASANI

22.32

2.69

0.11

6.50

1.0

8.0

0

0.45

9. (a)Give good reason (s) for the following. (Answer according to the question demand). Natural gas is so popular in heating and cooking in homes. (2 points)

  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

10. (a) Explain any three (3) economic importance of electrolysis.

(b)A current of 0.5A were made to flow through a silver voltammeter for 30 minutes. Calculate the mass of silver deposited at cathode.

11. (a)An organic compound is represented by the general formula CnH2n+2 (in each case n=1, 2, 3 ….). Write down the condensed structure formula and IUPAC names of the isomers of the fourth member from the above general formula.

(b)Write down the structures of the following compounds

  1. 5-iodo-4-methylhex-l-yne
  2. 6-methyl-4-propyloct -2-ene
  3. 2-fluoro-2, 3, 5, 5- tetramethylhexane.

12. During a practical session a tea spoon of common salt was being dissolved in 100mls of water but at different temperature to determine the effect of temperature on the solubility of a salt as shown below.

Volume of water (mls)

Temperature of water (°C)

Solubility of salt gram of water.

100

20

5

100

30

10

100

40

15

100

50

20

100

60

25

  1. Classify volume of water, temperature and solubility of salt into; dependent, independent and controlled variable
  2. Explain the application of scientific procedure in everyday life. (4 points)

SECTION C: (15 MARKS)

Answer only one question from this section.

13. What are the causes, effects and remedial measures of water pollution? (Give at least two points from each category)

14. (a)Explain the meaning of each of the following terms.

  1. Reversible reaction.
  2. Dynamic equilibrium

(b)The industrial oxidation of Sulphur dioxide is summarized in the equation below.

2SO3(g) + O2(g) 2SO3(g) H=-94.9 Kjmol-1

What will be the effect of each of the following on the production of Sulphur trioxide?

  1. Increase in moles of Sulphur dioxide
  2. Increase in pressure
  3. Decrease of temperature
  4. Decrease of moles of Sulphur dioxide.

(c)Briefly explain how each of the following factors affects the rate of a chemical reaction.

  1. Temperature
  2. Pressure
  3. Concentration
  4. Catalyst
  5. Surface area

(d)Give one good reason for the following

  1. Fruits ripe faster during summer than during winter
  2. Steel wire get rust faster than iron nails.

LEARNINGHUBTZ.CO.TZFORM FOUR CHEMISTRY REGIONAL SERIES-79 YEAR-2022

PRESIDENT'S OFFICE, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

ARUSHA REGIONAL FORM FOUR MOCK EXAMINATION 

032 CHEMISTRY 1

TIME : 3 Hours July 2022

INSTRUCTIONS

  1. This paper consists of section A, B and C with a total of fourteen (14) questions.
  2. Answer all questions in section A and B and one question from section C.
  3. Section A carries 15 Marks, section B carries 70 Marks and section C carries 15 Marks.
  4. All writing must be in black or blue ink except diagrams which must be in pencil.
  5. Cellular phones and any unauthorized materials are not allowed in the examination room.
  6. Non — Programmable calculator may be used.
  7. Write your NAME on every page of your answer sheets.
  8. The following constants May be used.

Atomic masses.

  • 0=16, H----1,C1-35.5, S-32, C-12, N = 14,Ca = 40,
  • Na=23, Cu = 64, Zn —65, S = 32,K= 39
  • Avogadro's constant = 6.02 x 1023 G.M.V. at S.T.P. = 22.4 dm3
  • 1 Faraday = 96500 coulombs 1 Litre ---- 1 dm3 = 1000 cm3

SECTION A (15 Marks) 

Answer ALL questions in this section

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

(i) Oxygen gas can be produced at a large by;

  1. Condensation of air 
  2. Condensation of liquefied air air
  3. Liquefaction of steam 
  4. Fractional distillation of liquefied
  5. Evaporation

(ii) Which of the following substance should not kept closely to the open bottle containing carbon-dioxide;

  1. Dilute nitric acid 
  2. Dilute hydrochloric acid 
  3. Sodium hydroxide solution
  4. Sodium nitrate
  5. Dilute sulphuric acid

(iii) The substance that can burn your skin is best described as: -

  1. Corrosive 
  2. Explosive 
  3. Flammable
  4. Toxic
  5. Oxidant

(iv) 10cmof 0.4M Sodium Hydroxide are added to 40cm3of 0.2M hydrochloric acid. The resulting mixture will be

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

(v) Which of the following Chemical species have the same number of electrons?

  1. K+, Ca2+, Cl- and Ar 
  2. O2-, Ca2+, Cland Mg2+ 
  3. Na+, Mg2+, Be2+and Na
  4. Cl, Na, K+and A13+
  5. K+, Ca2+, CI and Ne

(vi) When burette is used in the laboratory its calibration starts from above because.

  1. It measures the volume of remained
  2. It measures the used volume
  3. It measures the volume added
  4. It measures the volume of base added

(vii) Consider the following fuels which are used for-different purposes

1, Charcoal 2, Diesel 3. Coal 4. Fire wood

Which fuels are considered as secondary fuel?

  1. 1 and 4 
  2. 1 and 3
  3. 2 and 3
  4. 3 and 4
  5. 1 and 2

(viii) A metal nitrate which will not give a metal oxide on heating is:

  1. Calcium nitrate 
  2. Silver nitrate 
  3. Lead nitrate
  4. Copper nitrate
  5. Zinc nitrate

(ix) When nitrogen gas is formed covalently how many electrons are shared between nitroge atoms.

  1. 2
  2. 3
  3. 6
  4. 5
  5. 4

(x) Which substance can be reduced when heated with carbon;

  1. Alminium 
  2. Calcium carbonate 
  3. Iron III oxide 
  4. Magnesium oxide
  5. Sodium oxide

2. Match the items in List A with a correct response in List by writing the letter of the correct response below the corresponding item number.

List A List B

(i) Class A

(ii) Class B

(iii)Class C

(iv)Class D

(v) Class E

  1. Material such as circuit breakers, Aluminium. Propane, Paraffin
  2. Fire involving electrical equipment such as appliances, circuit breakers and outlets
  3. Metals such as Aluminum, Magnesium and titanium
  4. Flammable gases such as Propane, Butane, Methane and hydrogen
  5. Flammable liquids such as Paraffin, Petrol, Oil, Sprit and Alcohol
  6. Solids such as books, chair, tyres
  7. Substance like titanium, carbon dioxide and nitrogen

SECTION B (70 Marks) 

Answer ALL questions in this section

3. (a) (i) What types of a chemical bond is found between fluorine atoms in a fluorine molecule?

(ii) Name other type of chemical bond formed by Fluorine with other elements. Give an example.

(b) Compound X contains 24.24% Carbon, 4.04% hydrogen and 71. 72% Chlorine. Give that the vapour density of X is 49.5

(i) Calculate the molecular formula of compound X

(ii)    Name the molecular formula of compound X

(iii)Give the condensed structural formula of compound X

4. (a) Differentiate the temporary hardness of water from permanent hardness of water basing on their content.

(b) Consider the sample of water taken indifferent places at Arusha region. The samples were boiled and treated with the soap while others were treated with soap before boiling to obtain different results:

Sample Of Water Unboiled Boiled

Arusha Dc
Oldonyo Sambu
Maroroni
Njiro
Volume of Soap used(cm3)
1.0
8.5
10.5
5.9
Volume of Soap used(cm3)
1.0
8.5
3.8
1.0

(i) Which sample contains temporary hardness of water? (Give reason)

(ii) Which sample contains permanent hardness of water? (Give reason)

(iii)   What do you think will be the cause of variation of volume of soap of Maroroni water? 

(c) Mention the methods (s) used to soften sample of water at Njiro.

5.  (a) Explain how you can differentiate base (alkali) from acid in the Laboratory using Methyl    orange  (MO) and phenolphthalein (POP) indicators.

(b) 25cm3 of impure Sulphuric acid containing 5.2g/dm3 reacted with 25cmof sodium hydroxide solution made by dissolving 2g of sodium hydroxide in 500cm3 of water Calculate percentage purity and impurity of the acid the acid.

6.(a) A student accidentally broke a beaker containing Copper II Sulphate crystals. He decided to separate the blue crystals from small pieces of glass by first dissolving the mixture. What were his next steps?

(b) In the industrial preparation of sulphur trioxide equilibrium is established between sulphur dioxide and oxigen as follows:

(i) Is the forward reaction endothermic or exothermic? Give reason

(ii)How could you adjust temperature and pressure to maximize the proportion of product at equilibrium

(iii)Why it is unfavorable to work with very high pressure and very low temperature in the contact process

(iv) What catalyst is used to speed up the rate of the formation of Sulphur trioxide.

7. (a) With example in each differentiate alloy from allotropes.

(b) Carbon is one of the elements that have allotropes. Explain how two main allotrope of carbon differ from each other (4 points)

8. (a) Name three gases which should be not produced in order to prevent the destruction of ozone layer. (b) Explain for effects of ozone layer destruction.

9. Study the information in the table below and answer the questions that follow.

Element

Atomic number

V

12

W

13

P

16

R

18

1

19

M

9

(a) State the elements which belongs to the same period

(b)  (i) Identify element which is gaseous at room temperature

(ii) State an element which does not form an oxide

(iii) Give the chemical formula for the carbonate of element W.

(iv) Give a balanced chemical equation between the element which belong to alkaline earth metal and halogen above.

(c) Write balanced chemical equation when element I reacts with cold water.

10. (a) Consider the diagram below;


(i) Give aim of the above process

(ii) Identify the process A to F

(iii) Give two importance of the above diagram to our daily life.

(b) State whether the following is permanent change or temporary change,

(i) Dissolution of salt in water

(ii)    Rotting of mangoes

11. The diagram shows a set up to demonstrate the reaction between Chlorine and hydrogen sulphide gas.


(a) What will be observed when hydrogen sulphide gas is bubbled through chlorine water.

(b) Write an equation for the reaction between Chlorine and hydrogen sulphide.

(c) Give the name of the solid product formed in (b) above and write two uses of it.

(d) Which substance is an oxidizing agent and reducing agent in the above reaction.

12. Dilute nitric acid is added to a green solid P. A blue solution R is formed and gas I precipitate with lime water is formed. The blue solution R is evaporated to dryness and in the Pyrex test tube to give black solid M, brown fumes of gas W and colourless gas glowing splint was formed.

(a) Identify the substance P, R, I, M, Wand S

(b) Write the chemical equation for the;

(i) Dilute nitric acid and solid P

(ii) Formation of white precipitate with gas I and lime water.  

SECTION C (15 Marks)

Answer ONE (1) question from this section

13. With the aid of illustration, describe six methods of separating mixtures

14. (a) Give three (3) unique properties ca Carbon as a primary element in any organic compou, (b)Give the IUPAC name of the following;

(i) CH3C113 (iii)CH3COOCH3

(ii)    CH3CH CH2   (iv)CC14

(c) Write the open structure formula of the following;

(i) Pent-1 -ene

(ii) 2, 2- dimethyl butan-l-ol

(iii)3 - methyl but -1-yne

(iv)2,3 - dimethyl hex - 2 - ene

(d) Complete and balance the following organic reaction.



LEARNINGHUBTZ.CO.TZFORM FOUR CHEMISTRY REGIONAL SERIES-75 YEAR-2022

 PRESIDENT'S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT 

DAR ES SALAAM REGION & IRINGA- REGIONS FORM FOUR JOINT MOCK EXAMINATION - 2022 

CHEMISTRY - 1 

CODE: 032/1 

TIME: 3: 00 HOURS Friday 8th July 2022 A.M 

INSTRUCTIONS 

  1. This paper consist of sections A, B and C with a total of fourteen (14) questions
  2. Answer all questions in section A and B and one (1) question from section C
  3. Sections A and C carries Fifteen (15) marks each and section III carries seventy (70) marks
  4. Write your examination number of every page of your answer booklets

The following constants may be used. 

  • Atomic masses : [Na = 23, C = 12, 0 = 16, H = 1, CI = 35.5, Ag = 108, Cu = 64, Fe = 56, N = 14]
  • Avogadro's number = 6.02 x 1023
  • GMV at STP = 22.4 dm3
  • 1 Faraday = 96500 Coulombs
  • Standard pressure = 760 mmHg
  • Standard temperature = 273K
  • 1 litre = 1dm3 = 1000cm3

SECTION A (15 Marks)

Answer all questions in this section.

1. For each of the item (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)Which of the following contains a list of elements with the same number of electrons

  1. CL, He, Ne, O2-
  2. Na+,Mg2+,Be2+,Li
  3. K+,Ca2+,Cl-,Ar
  4. O2-, F-, Ne, Na
  5. Cl2, Mg2+,Al, Na+, Li

(ii) The molarity of 5.3g in 100ml of Na2CO3 solution is

  1. 0.2M
  2. 0.5M
  3. 0.05M
  4. 0.005M
  5. 0.01M

(iii) Which of the following compounds does Not belong to the Alkane homologous series

  1. C2H4
  2. CH4
  3. CsH12
  4. C3H8
  5. C4H10

(iv) The reaction between hydrogen and Iodine is represented by H2(g) + I2(g) 2HI(g) H=-xKJ/mol The reaction is

  1. Endothermic reaction
  2. Neutralization reaction
  3. Displacement reaction
  4. Exothermic reaction
  5. Decomposition reaction

(v) Chlorine gas was bubbled through distilled water. Then the distilled water turned pale yellow. Which of the following equations correctly show the reaction that took place?

  1. Cl2(g) + H2O(I) Cl2(g) +H2(g)
  2. Cl2(g) + H2O(I) HCl(aq) + HCIO(aq)
  3. 2Cl2(g) + H2O(I) 4Cl(aq) + O2(g)
  4. Cl2 + 2H2O(I) HOCl2 + H2O(I)
  5. Cl2(g) + H2O(I) HCl(aq) + H2O(I)

(vi) The following particles forms the nucleus of an atom

  1. Proton only
  2. Neutron and electron and Neutron
  3. Proton and Electron
  4. Proton and Electron
  5. Neutron and proton

(vii) One of the following apparatus is used to measure fixed volume of liquid

  1. Burette
  2. Pipette
  3. Conical flask
  4. Measuring cylinder
  5. Volumetric flask

(viii) A newspaper article claimed that carbon dioxide is formed as follows

  1. During respiration
  2. When calcium carbonate reacts with dilute HCI
  3. When methane burns completely in air. Which statement is correct
  1. 1, 2 and 3
  2. 1 and 2
  3. 1 and 3
  4. 2 and 3
  5. 1 and 2

(ix) Consider the following fuel which are used for different purpose

  1. Coal
  2. Firewood
  3. Petrol
  4. Charcoal

Which fuel originates from fossils?

  1. 1 and 3
  2. 2 and 4
  3. 1 and 4
  4. 2 and 3
  5. 3 and 4

(x) The following is an example of organic acid

  1. Hydrochloric acid
  2. Phosphoric acid citric acid
  3. Citric acid
  4. Nitric acid
  5. Carbonic acid

2. Match the descriptions in List A with the corresponding classes of fire in List B by writing the letter of the correct response beside the item number in the answer booklet provide.

LIST A

LIST B

  1. Burning material are flammable gas
  2. Burning material are cooking oils and fats
  3. Burning materials are flammable liquids
  4. Burning materials are solid organic materials
  5. Burning materials are combustible metals
  1. Fire class A
  2. Fire class B
  3. Fire class C
  4. Fire class D
  5. Fire class F

SECTION B.(70 MARKS)

Answer all questions from this section.

3. (a)Give three (3) ways in which environmental destruction is likely to occur during charcoal production.

(b)A form one student was asked to separate different mixtures in the laboratory. What methods used to separate the following components of mixture?

  1. Sand and Iron fillings
  2. Oil from nuts
  3. Iodine and sand
  4. Kerosene and water

4. Consider the following part of periodic table then use it to answer the questions that follows

  1. Name the elements represented by letters X, Q and Z
  2. (i) Write the electronic configuration of M and W

(ii) Which letter represent one metal and which letter represent one non-metal

5. (a) Briefly explain the concept of homologous series and give two characteristics of it

(b)Give the IUPAC names of the following compounds.

6. Exactly 15.8cm3 of 0.3M HCl solution were enough to neutralize 23cm3 of sodium carbonate solution prepared by dissolving 29.46g of the hydrated sodium carbonate (Na2CO3, XH2O) in a litre of solution. Find the value of X which is the number of molecules of water of crystallization

7. (a)what is the difference between electrochemical equivalent and chemical equivalent.

(b)During electrolysis of AgNO3 and CUSO4 solutions 5.4 gram of silver were deposited at the cathode. Find mass of copper and volume of oxygen gas at STP

8. (a)By giving reasons explain the facts that

  1. Chlorine gas is collected by upward displacement of air
  2. Ammonia gas is not dried by concentrated sulphuric acid
  3. Sulphur trioxide (SO3) is not directly dissolved in water to form sulphuric acid

(b) By using electronic diagrams show bonding occurs in the following

  1. Nitrogen molecule (N2)
  2. Sodium fluoride

9. Form four students conducted experiment in the laboratory to synthesize oxygen gas, Sulphur trioxide and hydrogen gas. Their experimental results were tabulated as follows.

Experiment 

Reagents 

Condition 

Products 

1

Potassium

Chlorate

  • Heat
  • Catalyst

Potassium

Chloride and oxygen gas

2

Zinc granule and dilute hydrochloric acid

Catalyst

Hydrogen gas

3

Sulphur dioxide and oxygen

Catalyst

Sulphur trioxide

  1. Write word equations with corresponding chemical equations to summarize the reactions taking place in each of the experiment 1 to 3
  2. What are the names of catalysts used in experiment 1 and experiment 3

10. (a)What do you understand by the following concepts

  1. Fertilizer
  2. Manure

(b)A farmer wanted to enrich his farm with nitrogen. He went to the shop and found the following fertilizer with their respective price.

Fertilizer 

Urea (NH2)2 CO

Price 

40,000/= Per bag

Ammonium nitrate

NH4NO3

40,000/= Per bag

11. (a)(i)How many chlorine molecules are present in 30cm3 of chlorine gas at STP?

(iii)What are the condition for a substance to be called matter?

(b)28 gram of Iron reacted as follows

2Fe(s) + 3Cl2(q)   2FeCl3(aq)

Calculate volume of chlorine gas at STP

12. (a)A form III student performed two different experiments

Experiment I: She dissolved one tea spoon of sugar in cold water.

Experiment II: She dissolved one tea spoon of sugar in hot water.

By using the concept of collision theory explain in which experiment the sugar dissolved more quickly?

(b)You are provided with the following equilibrium reaction

N2(g) + 3H2(g) 2NH3(g) + heat

What happens to the production of ammonia if

  1. Pressure increased
  2. The equilibrium system is cooled
  3. Hydrogen is removed
  4. Nitrogen is added

SECTION C (15 MARKS)

Answer one (1) question from this section

13. Most of areas in Dar es Salaam have a problem of water hardness which affect much their daily life activities. As an expert explain how can help them to solve the problem.

14. (a)What are the four (4) stages for extraction of moderate reactive metals is termed as reduction process. Explain why?

(b)Extraction of metals is termed as reduction process. Explain why?

(c)In certain areas iron can be extracted through blast furnace which involve different temperatures such as 1000°C, 750°C and 250°C in different stages.

  1. What is a chief ore in extraction of iron
  2. Write equations taking place in each of the named temperatures at what temperature reduction takes place
  3. At what temperature reduction takes place.
  4. What are the importance of coke, hot air and waste gases in the process above?

(d) What are the two (2) environmental effects caused by extraction of metals?

LEARNINGHUBTZ.CO.TZFORM FOUR CHEMISTRY REGIONAL SERIES-59 YEAR-2022

PRESIDENT'S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

KILIMANJARO REGIONAL COMMISSIONER'S OFFICE

FORM FOUR MOCK EXAMINATION

CHEMISTRY 1 CODE: 032/1

TIME: 3 HOURS 29/06/2022

INSTRUCTIONS

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

2. Answer all questions in section 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 unauthorized 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.

  • Atomic masses: H=l, C= 12, K=39, S= 32, 0=16, N=14
  • Avogadro's number = 6.02 x 1023
  • GMV at s.t.p 22.4 dm
  • 1 Faraday = 96,500 coulombs.
  • Standard pressure 760 mmHg
  • Standard temperature = 273 K.
  • 1 litre = 1 dm3=1000cm3

SECTION A (15 Mario)

Answer all questions in this section.

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

(i) Access to safety equipment should never be blocked by any object because

  1. It is just a simple law
  2. It is important to reach safety equipment quickly in case of an accident
  3. The equipment is used every day
  4. There must be space for people to move around in the laboratory
  5. The equipment used to avoid accident in the laboratory

(ii) What should be done if the results obtained from an experiment do not support the hypothesis?

  1. The results should be left out
  2. A new problem should be identified 
  3. The experiment should be changed
  4. Ideas for further testing to find a solution should be given
  5. The hypothesis should be accepted

(iii) Water exists in three forms, which are solid, liquid and vapour. Which among of the following are examples of liquid form of water

  1. Rain, snow and hail
  2. Dew, rain and ice
  3. Mist, steam and clouds
  4. Rain, hail, ice
  5. Rain, mist, and dew

(iv) Wind is a promising prospect source of energy in Tanzania because

  1. It cannot be seen easily
  2. It has high energy value
  3. Three are no chemical reactions involve in harvesting wind power
  4. It is renewable
  5. Does not produce harmful gases that pollute environment

(v) The reaction between potassium metal and water is REDOX reaction 2K(s)+2H2O(l)  → 2KOH(aq) + H2(g)

Which of the following statement is true about this reaction?

  1. The element hydrogen is oxidised
  2. The element potassium is reduced
  3. Potassium is the reducing agent
  4. Hydrogen is the reducing agent
  5. Water is both oxidised and reducing agent

(vi)The number of molecules of oxygen gas of volume 4,480cm measured at STP is:

  1. 2 x 1023
  2. 6.02 x 1023
  3. 1.204 x 1023
  4. 22.4 x 1023
  5. 3.0 x 1022

(vii) Emulsion is the mixture of liquids that do not completely mix with each other.

Which of the following set represent emulsion?

  1. Butter, lotion, toothpaste and milk
  2. Milk, gel, foam, sponge
  3. Cream, gel, lotion and paint
  4. Sponge, milk, smoke, insecticides
  5. Smoke, milk, paint and body spray

(viii) The formulae below represent some chemical substances. Which formula represent a substance that does not contribute to global warming

  1. H2
  2. CH4
  3. CO2 
  4. N2
  5. SO2

(ix) Domestic utensils made up of iron do rust as a result of the presence of

  1. Air and fire
  2. Water and oil
  3. Air and water 
  4. Air and oil
  5. Water and fire

(x) Ammonia is a basic gas that can be obtained by reacting ammonium salt and calcium hydroxide. Which of the following can be used as a drying agent of ammonia?

  1. Concentrated sulphuric acid
  2. Calcium chloride
  3. Lime water
  4. Calcium oxide
  5. Calcium carbonate

2. Match the properties of element in List A with the respective element in List B by; writing the letter of the correct response besides the item number in the answer sheet (s) provided.

LIST A

LIST B

(i) A black solid element which burns with reddish glow giving off colorless gas which is slightly acidic

(ii) Silvery white metal which burns with golden yellow flame giving an oxide which is basic in nature

(iii)A yellow element in color which burns with blue flame giving colorless gas which is strong acidic in nature

(iv) A shinning white strip metal burns with dazzling white flame giving an oxide which is slightly basic in nature

(v) A silvery white metal which burns with brick red giving off oxide which is white solid

  1. Calcium 
  2. Iron
  3. Sodium
  4. Zinc
  5. Magnesium
  6. Carbon
  7. Sulphur

SECTION B (70 Marks)

Answer an questions in this section

3. (a) The Modem periodic law is based on modification of Mendeleev periodic law. Explain how the two theories differ from each other.

(b) Comment on the following statement

(i) Lithium has large size than Beryllium

(ii) Sodium is smaller than potassium

(c) Give any four ions whose electronic configuration resemble to that of Neon. (07 Marks)

4. (a) A gaseous compound consists of 86% Carbon and 14% Hydrogen by mass. At S.T.P, 3.2dm3 of the compound had mass of 6g.

(i) Calculate its molecular formula

(ii)Give the IUPAC name of the compound

(b) Most of the apparatus in the laboratory are made up of glass materials. Support this statement by giving ant two (2) reasons. (07 Marks)

5. (a) Magnesium burns in a carbon dioxide living white solid and black solids sparks. The white solid dissolves in nitric acid leaving colorless solution R.

i. Write a balance equation for the reaction that gives the white solid.

ii. Identify solution R.

(b) In three points differentiate solution from suspension (07 Marks)

6. Msuya was given two gas jars, one containing gas "X" and another one containing gas "Z". Gas "X" is used prepare water gas in the industry and gas "Z" is used treating sewage plants.

(a) Identify those two gases

(b) (b)With reasons give the method used to collect gas "Z" in the laboratory

(c) Give three uses of gas "X" in our daily life (07 Marks)

7. A piece of marble chips (calcium carbonate) was placed in a beaker containing an excess of dilute hydrochloric acid standing on a reading balance. The mass of beaker and its contents was recorded after every two minutes as shown in the table below

Time (min)

0

2

4

6

8

10

12

14

Mass (g)

126.44

126.31

126.19

126.09

126.03

126.00

126.00

126.00

i. Why was there a loss of mass?

ii. Write the equation for the reaction 

iii. State three different ways in which the reaction could have been more rapid 

iv. Why did the mass remain constant after ten (10) minutes? (07 Marks)

8. (a) When an acid is reacted with base, it forms salt and water. Using your knowledge of chemistry, explain how will you apply this reaction in your daily life? Give any four points.

(b) Insoluble salts are the salt that does not dissolve in water. Name any three examples of salts that are insoluble in water. (07 Marks)

9. 16.8g of impure potassium hydroxide was dissolved in distilled water to make 1000mls. 20mls of this solution required 28mls of 0.07M sulphuric acid to react. Calculate:

(a) Molarity of KOH

(b) Mass Concentration of pure KOH (07 Marks)

10.During the manufacture of sulphuric acid, Sulphur trioxide gas is dissolved in concentrated sulphuric acid instead of dissolving it directly in water.

(a) Explain why? Write balanced equation of dissolution of the gas in the acid.

(b) Write a balanced chemical equation for each of the following 

(i) Sulphuric acid reacting as an acid

(ii) Sulphuric acid reacting as an oxidizing agent (07 Marks)

11. (a) Mrs. Janeth bought all necessary building materials as he wanted to build modern and expensive house for his mother, four months later he found out that almost all nails and Iron sheets have been rusted as she ignored leakage and small holes in the storage room, unfortunately he has no extra money to buy new nails and Iron sheets. As a chemistry student what will you advice Mrs. Janeth?

(b) Suppose you are in a bus traveling from Moshito Rombo for annual holiday, a bus driver went to the petrol station to fill fuel but he forgets to switch off the bus engine, this caused explosion and fire started. As a form four students:

(i) Will you be able to use fire extinguisher to fight against fire?

(ii) Which type of extinguisher will be suitable for you to use? Give reason of your choice (07 Marks)

12. (a) A farmer was cultivated crops every year but he produced low yields because the farm had low soil pH. As a chemists advice the farmers three methods used in modifications of soil pH.

(b) Differentiate soil fertility from soil productivity (07 Marks)

SECTION C.

Answer one (1) question from this section.

13. (a)Eutrophication is the excessive growth of aquatic plants and algae in water bodies

(i) Give two causes of eutrophication

(ii) Explain the effects of eutrophication

(b) Explain how industrial workers can be protected against harmful effects of the chemicals.

14. (a) With the aid of equations briefly explain the term substitution reaction as applied in organic Chemistry.

(b) With the use of chemical tests differentiate between saturated hydrocarbons and unsaturated hydrocarbons

(c) How can you convert ethane to ethane? Use equation.

(d) Write all isomers of Pentene


LEARNINGHUBTZ.CO.TZFORM FOUR CHEMISTRY REGIONAL SERIES-21 YEAR-2022

THE UNITED REPUBLIC OF TANZANIA PRESIDENT’S OFFICE, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

LUDEWA DISTRICT COUNCIL FORM FOUR MOCK EXAMINATION JUNE 2022.

032/1 CHEMISTRY 1

(For both school and private candidates)

Time 3 Hours 8th/06/2022 

INSTRUCTIONS

1. This paper consists of section A, B & c with a total of fourteen (14) questions.

2. Answer all questions in section A & 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

Atomic masses: H=1, O=16, S=32, Ca=40, Zn=65, Cl=35.5, Na=23, C=12, Ag=108

Avogadro’s number = 6.02 x 1023 GMV at s.t.p = 22.4dm3

1 faraday = 96,500 coulombs

1 litre = 1dm3 = 1000cm3

SECTION A (15Marks) 

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. Mr KALOBERO performed an electrolytic experiment on Calcium chloride.What number of faradays of electricity is required to deposit 4g of calcium from molten calcium chloride?

  1. 0.1
  2. 0.2
  3. 0.4
  4. 0.3
  5. 0.7

ii. Miss Mfwimi took methane and did substitution reaction with excess chlorine. What is the final product?

  1. Chloromethane
  2. Dichloromethane 
  3. Trichloromethane
  4. Tetracloromethane
  5. Monochloromethane  

iii. Mrs. Chakubanga mixed different metals uniformly. Which name is given to the uniform mixture of metals?

  1. Compounds
  2. Alloys
  3. Ores
  4. Salts 
  5.  Mixtures 

iv. Dr Mbogo did a certain reaction. The reaction was between iodine and hydrogen as represented by the following equations

The reaction is:-

  1. An endothermic reaction 
  2. A displacement reaction reaction
  3. A neutralization reaction 
  4. A thermal decomposition 
  5. An exothermic reaction 

v. A student teacher was in the class teaching how to write electronic configuration of different elements. The electronic configuration of this element Cl- is

  1. 2:8:7 
  2. 2:8:8
  3. 2:8:8:1
  4. 2:8:8:2 
  5. 2:8:6 

vi. When Mr Mwendakwao took Glucose and dissolved in water to form a uniform mixture.

  1. water is solution, glucose is solvent and the product is solute
  2. water is solute, glucose is solvent and the product is solution
  3. water is solvent, glucose is solute and the product is solution
  4. water and glucose forms immiscible mixture 
  5. water and glucose form emulsion

vii. Tell to Mr. Kitwanga, left white anhydrous copper (II) Sulphate in air turned blue. The reason why white anhydrous copper (II) Sulphate turns blue when exposed in Atmosphere is that it

  1. Absorbs water vapour 
  2. Reacts with oxygen 
  3. Reacts with carbon dioxide
  4. Become dry 
  5. Release water to the Atmosphere 

viii. In order for Mr. Kingunge to produce the greatest amount of hydrogen in a short time, one gram of magnesium ribbon should react with

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

ix. Mr. Kigwangala was just complaining about the increases of pollutant gases in the atmosphere causes the increase in temperature. but some gases cause acid were not present to Kigwangala’s complain. Make him understand what are the acidic oxides gases.

  1. Carbon dioxide, carbon monoxide and Sulphur dioxide.
  2. Sulphur trioxide, Nitrogen dioxide and Nitrogen 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. Mrs.Tupatupa spilled out concentrate acid on the floor. Which action should be taken immediately after concentrated Sulphuric acid is spilled on the skin?

  1. It should be rinsed off with large quantities of running water.
  2. It should be neutralized with concentrated NaOH
  3. The affected area should be wrapped tightly and shown to a medical health provider
  4. It should be Neutralize with solid CaCO3
  5. It should be neutralized with concentrated KOH

2 Match the items in List A with the response in List B by writing the letter of the corresponding responses beside the item number.

LIST A

LIST B

i. Biogas

ii. Biomass

iii. Natural gas iv. Producer gas

v. Water gas

  1. Industrial gas which is a mixture of hydrogen and carbon monoxide
  2. Non- renewable gaseous fuel
  3. Industrial gases fuel which is a mixture of nitrogen gas, hydrogen and carbon monoxide
  4. Gases fuel derived from decomposition of biological waste
  5. Renewable source of energy
  6. Water gas and ammonia
  7. Ammonia and butane

 SECTION B (70Marks)

Answer all questions in this section

3. (a)(i) A student from pre form one class asked you teach him the real meaning of Laboratory. What was you explained so as to make him understand the meaning of laboratory?

(ii) Mr. Kiseyeye wanted to prepare an oxygen. What are two main compound do Mr. Kiseyeye used in preparation oxygen gas in laboratory.

(ii)You as a student from form four class what do you think Why hydrogen gas is collected by downward displacement air method?

(b)Mr Kadinya don’t understand how to complete and balance chemical reactions. Help mr Kadinya to Complete and balance the following chemical reaction

i. NaOH(ag) + HCl(ag) →

ii. NH4Cl(ag) +NaOH(ag) →

iii. Ca(OH)2(ag) +H2SO→

iv. Mg(s) +HNO3(ag) 

4. Element R having atomic number 20 combines with element S having atomic number 17 to form a certain compound

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

b) Give any three properties of the compound formed in 7(a) above

5. .As a competent chemistry student chosen to present the topic of mole concept and related calculations. Show how will you present the following calculations

i. How many chlorine molecules are in 20cm3 of chlorine gas at s.t.p.

ii) Calculate number of ions present in 5g of copper (II) Nitrate

6. a) Muumini is a student from Katosani secondary school, she is not able to State Le Chatellier’s principle, Help her.

b) In the industrial preparation of Sulphur trioxide mr Atieno yo established equilibrium between Sulphur dioxide and oxygen gas as follows:

2SO2(g) + O2(g)  image 2SO3(g)∆H= - 94.9KJ/mol.

i. How would you adjust temperature and pressure to maximize the proportion of the product at equilibrium? 

ii. Why is it unfavorable to work with very high pressure and very low temperature in the contact process? 

iii. What catalyst is used to speed up the rate of formation of Sulphur trioxide before attaining the equilibrium?

7. a) You are tasked to explain the meaning of Molecular formula in a certain presentation that will be held next year. Present it now.

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.

8. In one of titration experiment 25cm3 of hydrated sodium carbonate Na2CO3.XH2O were titrated against 20cm3 of 0.25M hydrochloric acid. The solution of sodium carbonate was made by dissolving 7.15g of the compound in 250cm3 of distilled water.

Use the above data to answer the following questions

a) Write down a balanced equation to represent the acid base reaction

b) i. Find the morality of the an hydrated sodium carbonate ii. Calculate the value of X in the hydrated sodium carbonate.

9. a) Mr Mapulishi tasked to prepare all requirements for extraction of sodium.Describe the use of each of the following during extraction of Sodium

i. Calcium Chloride ii. Graphite anode

iii. Steel gauze

b) .Why sodium is collected by upwards in the downs cell

c) Write electrodes reaction in downs cell during extraction of Sodium

10. a) When I was in an interview at Feza boys’ secondary school, one student asked me to State Faraday’s Laws of Electrolysis. If you were me answer such question.

b) Dilute silver nitrate solution was decomposed by the passage of electric current through it. What mass of silver and what volume of oxygen (Measured at s.t.p) would be liberated in electrolysis by 9650 coulombs of Electricity?

11. Mr Kalubandika wanted to know some chemistry pertaining concepts. Help Mr Kalubandika to answer the following conceptual questions.

a) In which other areas do we find the warning signs out of laboratory (give four point)

b) Explain how measurements of volume differ when using measuring cylinder and burette

c) It is recommend that laboratory apparatus should be properly washed or wiped after use, explain the significance for this when

i. Measuring volume of liquids

ii. Measuring mass of substance

12. a) Mr Mwakatumbula don’t understand the physical properties of water. Teach him by giving three points the main physical properties of water and show the usefulness of each property.

b) Mr Kadinya said that Electrolysis is applied by many areas on the earth. State four industrial application of electrolysis

 SECTION C (15 MARKS)

13. We have coal at Kiwira in Mbeya region. Authorities in the government have allowed use of coal for domestic and industrial purpose. What warming can you raise concerning likely effects? Give five points

14. a). Explain the mechanism of electrolysis

b). briefly explain three application of electrolysis in our daily life

LEARNINGHUBTZ.CO.TZFORM FOUR CHEMISTRY REGIONAL SERIES-15 YEAR-2022

THE UNITED REPUBLIC OF TANZANIA PRESIDENT’S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

MWANZA CITY JOINT EXAMINATION (NYEGEZI, BUTIMBA AND MKUYUNI WARDS)

FORM FOUR PRE - MOCK EXAMINATION-2021

 CHEMISTRY 

Time 3:00 Hrs MAY, 2021

Instructions 

  1. This paper consists of section A, B & c with a total of fourteen (14) questions.
  2. Answer all questions in section A & 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
  • Atomic masses: H=1, O=16, S=32, Ca=40, Zn=65, Cl=35.5, Na=23, C=12, Ag=108
  • Avogadro’s number = 6.02 x 1023
  • GMV at s.t.p = 22.4dm3
  • 1 faraday = 96,500 coulombs
  • 1 litre = 1dm3 = 1000cm3

 SECTION A (15Marks)

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.

  1. What number of faradays of electricity is required to deposit 4g of calcium from molten calcium chloride?
  1. 0.1 
  2. 0.2 
  3. 0.4 
  4. 0.3 
  5. 0.7
  1. When methane undergoes substitution reaction with excess chlorine. What is the final product?
  1. Chloromethane
  2. Dichloromethane
  3. Trichloromethane
  4. Tetracloromethane
  5. Monochloromethane
  1. Which name is given to the uniform mixture of metals?
  1. Compounds 
  2. Alloys 
  3. Ores 
  4. Salts 
  5. Mixtures
  1. The reaction between iodine and hydrogen is represented by the following equations

I2(g) + H 2(g)  2HI (g)

The reaction is:-

  1. An endothermic reaction
  2. A displacement reaction
  3. A neutralization reaction
  4. A thermal decomposition reaction
  5. An exothermic reaction
  1. The electronic configuration of this element Cl- is
  1. 2:8:7 
  2. 2:8:8 
  3. 2:8:8:1 
  4. 2:8:8:2 
  5. 2:8:6
  1. Glucose dissolves in water to form a uniform mixture.
  1. water is solution, glucose is solvent and the product is solute
  2. water is solute, glucose is solvent and the product is solution
  3. water is solvent, glucose is solute and the product is solution
  4. water and glucose forms immiscible mixture
  5. water and glucose form emulsion
  1. The reason why white anhydrous copper (II) Sulphate turns blue when exposed in Atmosphere is that it
  1. Absorbs water vapour
  2. Reacts with oxygen
  3. Reacts with carbon dioxide
  4. Become dry
  5. Release water to the Atmosphere
  1. In order to produce the greatest amount of hydrogen in a short time, one gram of magnesium ribbon should react with
  1. 10cm3 of 0.5M Sulphuric acid
  2. 40cm3 of 0.5M acetic acid solution
  3. 40cm3 of 0.5 Sulphuric acid solution
  4. 20cm3 of 1M Sulphuric acid solution
  5. 20cm3 of 1M acetic acid solution
  1. Which of the following substances represent a group of acid oxides?
  1. Carbon dioxide, carbon monoxide and Sulphur dioxide.
  2. Sulphur trioxide, Nitrogen dioxide and Nitrogen 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.
  1. Which action should be taken immediately after concentrated sulphuric acid is spilled on the skin?
  1. It should be rinsed off with large quantities of running water.
  2. It should be neutralized with concentrated NaOH
  3. The affected area should be wrapped tightly and shown to a medical health provider
  4. It should be Neutralize with solid CaCO3
  5. It should be neutralized with concentrated KOH
  1. Match the items in List A with the response in List B by writing the letter of the corresponding responses beside the item number.

LIST A

LIST B

(i) Biogas

(ii) Biomass

(iii) Natural gas

(iv) Producer gas

(v) Water gas

  1. Industrial gas which is a mixture of hydrogen and carbon monoxide
  2. Non- renewable gaseous fuel
  3. Industrial gases fuel which is a mixture of nitrogen gas, hydrogen and carbon monoxide
  4. Gases fuel derived from decomposition of biological waste
  5. Renewable source of energy
  6. Water gas and ammonia
  7. Ammonia and butane

 SECTION B (70Marks)

Answer all questions in this section

3. (a)

  1. What is laboratory?
  2. Name two main compound used in preparation oxygen gas in laboratory
  3. Why hydrogen gas is collected by downward displacement method?

(b) Complete and balance the following chemical reaction

  1. NaOH(ag) + HCl(ag) 
  2. NH4Cl(ag)  +NaOH(ag) 
  3. Ca(OH)2(ag)  +H2SO4(ag) 
  4. Mg(s)   +HNO3(ag)

4. Element R having atomic number 20 combines with element S having atomic number 17 to form a certain compound

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

(b) Give any three properties of the compound formed in 7(a) above

5. a) How many chlorine molecules are in 20cm3 of chlorine gas at s.t.p.

b) Calculate number of ions present in 5g of copper (II) Nitrate

6. a) State Le Chatellier’s principle.

b) In the industrial preparation of Sulphur trioxide equilibrium is established between Sulphur dioxide and oxygen gas as follows:

 2SO2(g) + O2(g) O3(g)∆H= 94.9KJ/mol.

  1. How would you adjust temperature and pressure to maximize the proportion of the product at equilibrium?
  2. Why is it unfavorable to work with very high pressure and very low temperature in the contact process?
  3. What catalyst is used to speed up the rate of formation of Sulphur trioxide before attaining the equilibrium?

7.(a) What is molecular formula?

(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.

8. In one titration experiment 25cm3 of hydrated sodium carbonate Na2CO3.XH2O were titrated against 20cm3 of 0.25M hydrochloric acid. The solution of sodium carbonate was made by dissolving 7.15g of the compound in 250cm3 of distilled water.

Use the above data to answer the following questions

  1. Write down a balanced equation to represent the acid base reaction
  2. i. Find the morality of the an hydrated sodium carbonate

ii. Calculate the value of X in the hydrated sodium carbonate.

9. (a)Describe the use of each of the following during extraction of Sodium

  1. Calcium Chloride
  2. Graphite anode
  3. Steel gauze

(b).Why sodium is collected by upwards in the downs cell

c). Write electrodes reaction in downs cell during extraction of Sodium

10. (a) State Faraday’s Laws of Electrolysis

(b) Dilute silver nitrate solution was decomposed by the passage of electric current through it. What mass of silver and what volume of oxygen (Measured at s.t.p) would be liberated in electrolysis by 9650 coulombs of Electricity?

11. (a) In which other areas do we find the warning signs out of laboratory (give four point)

(b) Explain how measurements of volume differ when using measuring cylinder and burette

(c) It is recommend that laboratory apparatus should be properly washed or wiped after use, explain the significance for this when

  1. Measuring volume of liquids
  2. Measuring mass of substance

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

(b) State four industrial application of electrolysis

 SECTION C (15 MARKS)

Answer one (1) question in this section

13. (a) How can you tell water is polluted? Give two ways

(b) We have coal at Kiwira in Mbeya region. Authorities in the government have allowed use of coal for domestic and industrial purpose. What warming can you raise concerning likely effects? Give five points

14. (a) Define the following terms

  1. functional group
  2. homologous series
  3. isomerism

(b) Write down the molecular structure and the IUPAC names of the isomer whose molecular structure is C4H10

(c) By naming the reagents, stating the conditions whenever possible using a balances equation describe how ethane could be converted into

  1. Ethane
  2. Chloroethane
  3. 1,2-dibromoethane
  4. Ethanol

LEARNINGHUBTZ.CO.TZFORM FOUR CHEMISTRY REGIONAL SERIES-69 YEAR-2021

THE PRESIDENT’S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT 

KILOSA DISTRICT COUNCIL MIKUMI (MAU)

FORM FOUR PRE - MOCK JOINT EXAMINATION

032/1 CHEMISTRY 1  

(For School Candidates Only)

TIME:  3:00 Hours Friday March 19, 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. Non-programmable calculators may be allowed.

4. Cellular phones and any unauthorized 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: Atomic masses:

  • Atomic masses; H = 1, O = 16, Na = 23, C = 12, Cl = 35.5, N =14, Zn = 65, S = 32, Ca = 40, Fe = 56, Cu = 64, Al = 27 .
  • GMV at s. t. p = 22.4dm³
  • Avogadro’s number = 6.02 x 10²³
  • 1Faraday = 96500coulombs
  • 1Litre = 1dm³ = 1000cm3

SECTION A (15 MARKS)

1. For each of the items (i – x) choose the correct answer from the given alternatives and write it’s letter in the booklet provided

(i) A substance which absorb water from the atmosphere and form a solution is called

  1. Efflorescent 
  2. hygroscopic 
  3. deliquescent
  4. amphoteric

(ii) Technicians prefer to use blue flame in welding because

  1. It is bright and non soot 
  2. it is light and non soot 
  3. it is very hot and non soot 
  4. it is not expensive

(iii) Chlorine ion Clˉ differ from chlorine atom because it has

  1. More proton 
  2. less proton 
  3. more electron 
  4. less electrons

(iv) AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNo3(aq). This a good example of

  1. Neutralization reaction 
  2. double decomposion reaction 
  3. Redox reaction 
  4. synthesis reaction

(v) The volume of 0.2M of H2SO4 acid required to neutralize completely 25.00cm³ of 0.05M KOH is

  1. 0.626cm³ 
  2. 3.125cm³ 
  3. 12.500cm³ 
  4. 6.315cm³

(vi) An electric current was passed through concentrated hydrochloric acid using carbon electrodes. The substance liberated at the anode was

  1. copper 
  2. Chlorine 
  3. oxygen 
  4. hydrogen.

(vii) An example of a homologous series is

  1. methane ,ethane, propane 
  2. propane, butane, pentyne 
  3. ethane, propene, butyne 
  4. ethene, propane, butane.

(viii)A covalent bond is formed when

  1. ammonia is formed 
  2. potassium and oxygen combine 
  3. a metal combines with non metal 
  4. an atom loses an electron .

(ix) The empirical formula of a certain compound is CH3.Its molar mass is 30g/mol , what will be its molecular formula

  1. C2H6 
  2. CH4 
  3. C2H8 
  4. C2H4

(x) …… is the general terms used to explain a mixture of different metals

  1. Amphoteric 
  2. allotrope 
  3. isotope 
  4. Alloy

2. Match the item in LIST” A” with the correct response in LIST” B”

LIST A

LIST B

(i) Methyl orange indicator 

(ii) Calcium hydroxide 

(iii) pH 2

(iv) Neutralization reaction

(v) Sodium hydrogen sulphate

  1. Normal salt
  2. Concentrated base
  3. image
  4. Composition reaction
  5. Strong acid + weak base
  6. Slaked lime
  7. Strong base + weak acid
  8. Acidic salt
  9. Concentrated acid
  10. Neutral salt

SECTION B (70 MARKS)

3. (a) Write balanced equation of

(i) Sodium hydroxide react with sulphuric acid

(ii) Calcium carbonate decomposed by heat

(b) (i) With aid of a balanced chemical equation name the products formed when nitrates of potassium and zinc decompose by heat

(ii) Suggest why nitrates of zinc and potassium behave differently on heating

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

(ii) Give four compounds found in the laboratory which show the same characteristic as ashes. 

(b) How many ions are there in 6.82g of Al2(SO4)3

5. (a) Copy and complete the following table

Element

A

B

C

D

Number of proton




16

Number of neutron

6

12



Mass number



39

32

Electronic configuration


2:8:1



(b) (i) Write balanced chemical equation for reaction between B and D

(ii) Write the molecular formula of a compound formed when C combine with D

6. A students tested four sample of water each 10cm³ from different areas at Malawi village by shaking with tree drops of soap solution. The experiment was repeated a second time by boiling each sample of water (10cm³) with three drops of soap solution. The observation were recorded as shown in the table below

Sample

Observation with soap solution

Observation for boiled sample with soap

A

No lather

Lather

B

Lather

Lather

C

Lather

Lather

D

No lather

No lather

a) Which sample contains only temporary hard water? Give reason

b) Which sample contain permanent hard water? Give reason

c) Name the chemical substances that would be the causes of hardness in sample “A”

d) Write the chemical equation for removing hardness in

(i) Sample “A”

(ii) Sample “D”

7. (a) (i) State faraday’s first law of electrolysis

(ii) Using the law stated above, derive mathematical expression of faraday’s first law of electrolysis

(b) How many moles of electrons will be transferred if Zinc metal is produced by a current of 14.23A supplied for 8.0 HRS.

8. 5.3g of X2CO3 was dissolved in water to make 0.5 litre of a solution. 25cm³ 0f this solution required 50.0cm³ of 0.1M HCl for complete neutralization.

a) Write the balanced chemical equation for the reaction

b) Calculate the concentration of X2CO3 in mol/dm3

c) Calculate the relative molecular mass of X2CO3

d) Calculate the relative atomic mass of X

e) What is the name and symbol of element X

9. (a) Give two example in each of the following

(i) Solid fuel (ii) Gaseous fuel

(b) The reaction which produces methanol from carbon monoxide and hydrogen is represented by the equation 

.The reaction is carried out at high pressure to give a better yield of methanol

i) Explain why increase in pressure gives a better yield of methanol. 

ii) The value of  is negative . What does this tell about the reaction

iii)With reason state whether a high temperature or low temperature will give a better yield of methanol.

10. Draw the well labeled diagram of laboratory preparation of oxygen using the mixture of potassium chlorate and manganese 

(iv)oxide

11. (a) Define the oxidation state

(b) Calculate the oxidation state of the underlined element in the following compounds

12. (a) Define the following

i)A homologous series 

ii) Hydrocarborns iii) Isomerism

(b) Write the structure formulae of all possible isomers of hydrocarbon whose formula is C4H10 and give the IUPAC names.

SECTION C (15 MARKS)

Answer only one (1) question from this section

13. With the aid of the balanced chemical equations explain the processes that occurs in the blast furnace during extraction of iron.

14. Environment support lives of all organism. Its pollution has led to some major catastrophic effects. Describe water pollution by analyzing it’s causes, effect and the protective and remedial measures be taken.

LEARNINGHUBTZ.CO.TZFORM FOUR CHEMISTRY REGIONAL SERIES-52 YEAR-2021

PRESIDENT’S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

FORM IV MOCK EXAMINATION 2020 DODOMA REGION

032/1  CHEMISTRY 1

Time: 3 Hours Thursday, 6th August 2020 a.m.

Instructions

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

2.Answer all questions from section A and B and one (1) question from section C.

3.Except for diagrams that must be drawn in pencil, all writing should be done using a blue or black pen.

4.Calculators and cellular phones are not allowed in the examination room 5. Write you Examination number on every page of your answer sheets/booklet(s)

6. The following constants may be used:

Atomic masses: H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Cu = 63.5 and Pb =207

Avogadro’s number = 6.02 x 1023mol-1

GMV at s.t.p = 22.4 dm3mol-1

1 Faraday = 96500 Coulombs

Standard temperature = 273 K

1 litre = 1 dm3 = 1000 cm3

SECTION A (15 Marks)

Answerall questions in this section

1. For each of the following items (i) – (x) choose the correct answer among the given alternatives and write its letter beside the item number in the answer sheet(s) provided

(i) Splints are among the first aid kit components. Which of the following sentences best describes its use?

A. Used for cutting bandages or piece of cloth

B. Used for holding pieces of bandages or cloth together

C. Used to support broken bones and is tied using bandages

D. Used for picking up and holding things

E. Used for cleaning wounds and make it heal faster

(ii) A simple proof that some chemical reactions take place in our bodies is that

A. We eat a balanced diet

B. Doctors tell us so in the hospitals

C. We occasionally fall sick

D. The food we eat or the drinks we take are quite different from the waste products from our bodies

E. There is no proof

(iii) The following reaction, 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g), is an example of a

A. Decomposition reaction

B. Combination reaction

C. Redox reaction

D. Neutralization reaction E. Esterification reaction

(iv) An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change?

A. Baking powder 

B. Lime 

C. Aqueous ammonia  

D. Vinegar 

E. Quick lime

(v) Oils on treating with hydrogen in the presence of nickel catalyst form fats. This is an example of

A. Oxidation reaction

B. Addition reaction

C. Displacement reaction  

D. Substitution reaction

E. Precipitation reaction

(vi) Three elements T, Q and R, are in the same period of the periodic table. The oxide of T is amphoteric, the oxide of Q is basic and the oxide of R is acidic. Which of the following shows the elements arranged in order of increasing atomic number?

A. T, Q, R 

B. Q, T, R

C. Q, R, T

D. R, T, Q

 E. T, R, Q

(vii) What happens when dilute sulphuric acid is poured on copper plate?

A. Zinc sulphate formed D.Copper chloride formed

B. Zinc chloride formed E.None of the above C. Copper sulphate formed

(viii) The oxidation state of chlorine in potassium chlorate is

A. + 1 C. + 5 E. + 6

B. + 7 D. – 1

(ix) Ammonia gas is collected by which method among the following? 

A. Downward displacement of water

B. Upward delivery

C. Downward delivery

D. Upward displacement of air

E. Collected over water

(x) Ten gram of copper powder were placed in a sealed initiation tube containing air. The tube was heated very strongly for half an hour. At the end of the experiment

A. Water vapour appeared in the tube

B. Undergoes decomposition

C. The total mass of the tube and its contents decreased

D. Copper melted into a liquid copper form

E. Copper increased in mass and changed in colour

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 sheet or booklet provided.

List A

List B

  1. When air is pumped into test tube contain lime water, lime water turns milky
  2. Condition for iron to rust
  3. Oxygen, Heat and Fuel
  4. Coating of Iron or steel with Zinc
  5. Flammable liquids like petrol, alcohol and kerosene

A. Water is used for extinguishing

B. Oxygen and water/moisture

C. Presence of Oxygen

D. Fire triangle

E. Presence of carbon dioxide

F. Rusting

G. Galvanization

H. Class B fire

I. Nitrogen

SECTION B (70 Marks)

Answerall questions in this section

3. (a) The table below shows two brands of bottled water for drinking and the concentration of different mineral ions in each brand. Study the table and answer the questions below it.

Composition in mg/Litre

Mineral

Na+

Ca2+

Mg2+

Cl

NO3

SO42-

Fe2+

F

Uhai

40.0

3.05

4.15

14.18

0.48

10.0

0

1.76

Dasani

22.32

2.69

0.11

6.50

1.0

8.0

0

0.45

(i) Which brand of water is more hard? Explain.

(ii) State the benefit of having calcium ions in water;

(iii)Tap water is usually treated before being used. State what is added to perform that function.

(b) Hydrogen and phosphorus are non-metallic elements

(i) Which one between the two atoms is more electropositive?

(ii) Show your work clearly, write the chemical formula and the name of the compound formed when the two atoms combine.

4. One of the methods used for the preparation of oxygen is by the decomposition of hydrogen peroxide as shown in the reaction equation below

image2(g)

(a) (i) What is the purpose of MnO2 in the reaction?

(ii) What will happen to the rate of the reaction if MnO2 is not used in the above reaction?

(b) Briefly explain how the gas produced from the chemical reaction above is tested

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

(i) Wood charcoal

(ii) Coke

(iii)Lamp black

(iv) Animal charcoal

(b) Name two main products formed when

(i) Hot concentrated sulphuric acid is added to sugar cane (ii) Hot concentrated sulphuric acid is added to ethanol

6. (a) Define the following terms

(i) Mole

(ii) Molar mass

(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 produced.

7. A gaseous compound consists of 86% carbon and 14% hydrogen by mass. At s.t.p., 3.2 dm3 of the compound had mass of 6 g. Calculate its molecular formula

8. (a) Study the following reaction equation N2(g) + 3H2(g)image 2NH3(g) ∆H = - 46.2 kJmol-1

Use Le-Chatelier’s principle, suggest how you would use temperature and pressure to obtain the highest production of ammonia at equilibrium

(b) The formation of methanol from hydrogen and carbon monoxide can be represented by

CO(g) + 2H2(g) image CH3OH ∆H = 91 kJmol-1

What mass of hydrogen would react to cause a heat change of 91 kJ

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

(i) Soil pH (ii) Liming

(b) (i) Explain why sulphur and its compounds are removed from the fuel before they are burned

(ii) By using a reaction equation explain how propane differs from propene

10. (a) Outline any three uses of carbon dioxide gas in animals and plants

(b) Complete the following reactions

(i) CH2=CH2 + O2image

(ii) CaC2 + 2H2O image

(iii)CH4 +Cl image

(iv) C2H5OH +O image

11. (a) (i) What is the aim of having fume chamber in the chemistry laboratory?

(ii) Why laboratory doors are open outward?

(b) State the use of the following

Item

Use

(i)

Cotton wool

(ii)

Petroleum jelly

(iii)

Pain killers

(iv)

Bandages

(v)

Razor blade

12. (a) With examples list four types of oxides

(b) Give any three types of salts

SECTION C (15 Marks)

Answer only one question in this section

13. Explain six (6) methods of preventing water pollution

14. In certain chemical plant that deals with the production of hydrogen gas, a certain chemist passes an electric current in series through copper (II) sulphate and sulphuric acid solutions. In both electrolytes, inert electrodes were used. If 8400 cm3 of hydrogen gas at S.T.P were produced for several hours, what volume of oxygen gas would also be produced? What mass of copper was produced?

LEARNINGHUBTZ.CO.TZFORM FOUR CHEMISTRY REGIONAL SERIES-10 YEAR-2020

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