CHRISTIAN SOCIAL SERVICES COMMISSION- (CSSC)

WESTERN ZONE

FORM TWO JOINT EXAMINATION

CODE: 032  CHEMISTRY

TIME2:30HRS  Date: 30^th August, 2023

INSTRUCTIONS:

1. This paper consists of section A, B, and C with a total of ten (10) questions.
2. Answer all questions in the spaces provided
3. Section A carries (15) marks, section B carries (70) marks and section C carries seventy (15) marks.
4. All communication devices and any unauthorized materials are not allowed in the examination room.
5. Write your examination number on every page
6. All writings should be in blue/black ink, all diagrams should be drawn in pencil.
7. The following atomic masses may be used.

• H=1, N=14, O=16, Na=23

SECTION A: (15 marks)

1. For each items i-x, choose the correct answer from among the given alternatives and write its letter in the space provided.

i. the best method of separating a mixture of sodium chloride and ammonium chloride is:

1. Sublimation
2. Layer separation 
3. Decantation
4. Chromatography

ii. The formula below represents some chemical substances. Which formula represents hydrated copper (ii) sulphate?

1. Cu₂ S₂  O₄
2. CuSo_2.  5H₂O 
3. CuSO₄
4. CuSO_4.  5H₂O

iv. Mwl. Adasa from St. Francis exavier secondary school during making the general cleanliness at her home, she found a bottle of coca cola written the term “composition” the bottle was left by her daughter Divine on the table.. What does the term mean in chemistry?

1. Break down of matter
2. Waste disposal
3. Suspension
4. Building up of matter

v. Joel is a meteorologist at Mwanza weather station. He wants to use weather balloons so as to record information on the elements of weather.

Which gas would you advise him to use for filling weather balloons?

1. Hydrogen
2. Nitrogen gas 
3. Oxygen gas
4. Noble gas

vi. In Haramba’s office, there are many rust utensils made up with element called iron. These utensils can undergo rusting if they are exposed to:

1. Air and fire
2. Air and water
3. Air and palm oil
4. Air and soil

vi. Using the abbreviation ^x_yJ and J is an element, x is a mass number and y is atomic number. Choose the list that contains isotopes of the same element.

1. 1J2, 3J6, 4J8
2. 1J1, 2J1, 3J1
3. 1J1, 1J2, 1J3
4. 2J2, 4J4, 6J6

vii. An element from Alkali metals reacts with carbonate. What is the probable chemical formula of that Alkali carbonate?

1. ACO₃
2. A₂ (CO₃)₂        
3. A₃CO
4. A₂CO₃

viii. Form one students saw a sheet of paper in the chemical laboratory written as “sulphuric acid is a strong acid”. In warning signs sulphuric acid is …

1. Very corrosive chemical
2. Highly flammable
3. Strong oxidizing agent
4. Strong metal

ix. Gabriel gets burnt accidentally during cooking rice at home. he would be given one of the following as first aid:

1. Iodine solution
2. Gentian violet
3. Clinical thermometer
4. Soap

x. If you want the Bunsen burner flame to have the same colour as that of a candle, then you must:

1. have the air hole fully opened
2. have raised the burner
3. have the air hole fully closed
4. turn off the gas supply

Answers:

2. Match the items in list A with response in list B by writing the letter of the correct response in the table provide below.

Answers

SECTION B: (70 marks)

Answer all questions in this section

3. By giving one reason, explain the following facts.

i. During laboratory preparation of oxygen gas little manganese dioxide is added to hydrogen peroxide.

Reason:__________________________________________________________________

__________________________________________________________________

ii. Fish can obtain oxygen for respiration although they spend their lives in water. Reason:__________________________________________________________________

__________________________________________________________________

iii. Oxygen gas can be used for welding activities although it does not burn.

Reason:__________________________________________________________________

__________________________________________________________________

iv. Nyanda gets confusion on how hydrogen gas properties relates with its uses. Assist Nyanda on how the properties of hydrogen can relate with its uses.

4. (a) The structure of the atom is successive improvement of various models advanced by different scientists. John Dalton was the first scientist to suggest on the structure of atom. However, his model failed to explain some observations.

State any four (4) Modifications made on Dalton’s atomic theory.

i. __________________________________________________________________

ii. __________________________________________________________________

iii. __________________________________________________________________

iv. __________________________________________________________________

(b) If the relative atomic mass of element P is 16.2. But P has X% of ^y₈P and 90% ¹⁶₈P. Calculate the value of x and y.

5. Niyonkulu is an expert environmental conservation. He was invited by WEO of Janda village to educate people about the environmental effects of using charcoal as the source of fuel but he did not attend the meeting. As a from two student use that vacancy to educate Janda villager’s. (Three points)

(b) Identify three materials produced from destructive distillation of coal.

(c) A mass of 20.0 g of kerosene was burnt in air. The heat produced was used to heat 2.5 litres of water. Given that the heat value of kerosene is 43, 640 kJ/Kg. By how much the temperature of water could have changed?

Use: The specific heat capacity of water=4.18 kJKg^-1K^-1 Density of water1000Kg/m³

6. (a) With one example, give the meaning of the following the following terms as applied in chemistry.

i. Radical

__________________________________________________________________

__________________________________________________________________

ii. Oxidation state

__________________________________________________________________ __________________________________________________________________

(b) Find the oxidation number of the following underlined elements.

i. Al

ii. HNO₃

iii. Cr2 O72-

iv. Al₂(SO₄)₃

v. S2O32-

7. Mixing of different substances involves chemical and physical changes. state whether the following is physical or chemical change

i. A match is lit _________________________________________

ii. Grinding a piece of chalk ___________________________________________

iii. Rice is cooked _________________________________________

iv. Drying of paper __________________________________________________

v. Iron sheet rust ___________________________________________________

(b) Grace went into the laboratory and found five bottles with different mixtures. The bottles were labeled A, B, C, D and E which contains Alcohol and water, iodine and sand, cooking oil and water, water and salt, maize grain and sand respectively. Which method will she use to separate mixtures on those bottles?

Bottle A- ___________________________________________________________

Bottle B- ___________________________________________________________

Bottle C-_____________________________________________________________

Bottle D-_______________________________________________________________ Bottle E-________________________________________________________________

8. (a) Differentiate between empirical; formula and molecular formula.

Empirical formula

________________________________________________________________________

________________________________________________________________________

Molecular formula

________________________________________________________________________

________________________________________________________________________

(b) An organic compound contains 72.8% carbon, 7.2% hydrogen and the percentage composition rest was for oxygen. If it’s relative molecular mass is 164.

Determine its;

i. Empirical formula

ii. Molecular formula

9. Fill in the following by giving any two products that are made by the application of chemistry in each of the field shown.

(b) State the uses of the following laboratory apparatus

i. Safety goggles ____________________________________________________

ii. Spatula __________________________________________________________

iii. Tongs ____________________________________________________________

iv. Reagent bottle ____________________________________________________

v. Plastic wash bottle ________________________________________________

SECTION C: (15 MARKS)

10. (a) Construct the diagram to show the electronic structure in each of the following compounds

i. Oxygen gas (O₂)

ii. Ammonia (NH₃)

iii. Table salt

(b) What type of bond exists in the compound in part (a)?

i. Oxygen gas _______________________________________________________

ii. Ammonia ____________________________________________________________

iii. Table salt ______________________________________________________________

(c) Give out three differences on the type of bond exists in the compound (a) i and (iii)

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

MOROGORO REGION

FORM TWO REGIONAL ASSESSMENT 

CODE: 032 CHEMISTRY -2023

TIME: 2.30 HOURS YEAR: 2023

INSTRUCTIONS

1. This paper consists of section A, B, and C with a total of Ten (10) questions.
2. Answer all questions in all sections.
3. Answer all questions in the spaces provided.
4. All writings 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. The following constants can be used: atomic masses: 

• H=l, 0=16, C=12 Na=23, S=32, Specific heat capacity of water 4.18kJkg -1 k-1

SECTION A (15 MARKS)

Answer all question in this section

1. For each of the item (i -x), Choose the most correct answer from among the given alternatives and write its letter in the space provided below.

i) Which of the following is unlikely to produce soot?

1. Complete combustion
2. incomplete combustion
3. limited supply of air burning
4. luminous flame

ii) The mixture of cooking oil and water can be termed as

1. Suspension 
2. Emulsion 
3. Solution
4. Saturation

iii) Experimentation in chemistry is used to test.

1. Observation. 
2. Hypotheses. 
3. Data.
4. Problem.

iv). Hydrogen has three isotopes ¹H (99.99%), ²H (0.01) and ^3H (rare). Its relative atomic mass is?

1. 1.10 
2. 2.01
3. 3.10
4. 1.001

v) State of matter depend on

1. Tensile strength
2. Property of atoms
3. Arrangement of particles
4. Temperature change

vi) The process of coating iron or s eel with zinc is known as

1. Zinc painting. 
2. Alloying. 
3. Tin plating.
4. Galvanization

vii) A class of fire that cannot be extinguished by water due to different in densities

1. Class C 
2. Class D 
3. Class E
4. Class B

viii) Element with atomic 2 is likely to have similar properties to element with atomic number.

1. 18 
2. 9 
3. 12
4. 7

ix) The gas that turn lime water milky

1. Sulphur dioxide 
2. Nitrogen dioxide 
3. Carbon dioxide
4. Carbon monoxide

x) If K and Y are isotopes of the same element, then K and Y have the same.

1. Mass number.
2. Atomic weight
3. Atomic Number
4. Number of neutrons

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

SECTION B (70 MARKS)

Answer all questions in this section

3. a) Hydrogen gas is prepared in the laboratory in different ways. The most common method is by the action of dilute acids on metals

i. Draw a neat well labeled diagram for the laboratory preparation of hydrogen gas

ii. Write a balanced chemical equation for this laboratory preparation of hydrogen gas

b) Relating to its property on each explain two uses of hydrogen gas.

b) Given that element 13G reacts with element Using electronic configuration write the formula of the compound formed (G and X are not the actual symbols of the elements).

c) Briefly explain any two importance of changes of states of matter.

5. a) Identify types of change involved in each of the following. i.e. state whether physical or chemical change,

i) Respiration ii) Sublimation iii) Combustion iv) Distillation

b)Write the chemical symbols of the following elements

i) Potassium ii) Sodium iii) Mercury iv) Gold

c) Write the most suitable method of separating the following mixture.

i) Air
ii) Kerosene and water
iij) Iodine and sand

iv) Syrup

6. A compound consists of 27.3% sodium, 1.2% hydrogen, 14.3% carbon a nd oxygen. Its relative atomic mass is 84

i) Calculate its empirical formula

a. Use the answer in 6(i) to find its molecular formula

ii) State the name of the compound

7. a) Briefly explain how periodicity contributed in the preparation of the modern periodic table.

b) Although elements in the periodic table are arranged in such a way that elements with similar properties are placed in the same group. There some trends across the period and down the group. Giving reason(s) for each, briefly explain the trends of electronegativity and electro positivity

i) electro-positivity

ii) electro-negativity

7. (a) Dalton's ideas contributed a lot about the explanation and the atom but does not describe the structure of the atom. State four assumptions of Dalton atomic theory.

b) Assume Boron has two stable isotopes 10B (39.78%) and 11B. Calculate the average atomic mass of Boron.

8. a) Elements 40W has 22 neutrons (the letter is not the actual symbols of the element). State the element's:

i) Atomic number

ii) Number of protons

iii) Electronic configuration

iv) Name of element W

b) Element G is in group 7 period 3.

i) Write the atomic number of G

ii) Write the nuclide notation of two isotopes of G

SECTION C (15 MARKS)

9. a) At Grace's village livestock keeping especially cows is the main economic activity. Most of the villagers use fire wood as their main source of fuel. Educate them on the dangers they are likely to face if they continue using fire wood (four points) and advise them the alternative source of fuel to use.

b) The heat value of kerosene is 43400kJkg-1. Calculate the mass of kerosene that is required to rise the temperature of 20kg of water from 293k to 333k.

PRESIDENT’S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT  MVOMERO DISTRICT COUNCIL

Instructions

1. This paper consist of sections A, B, and C with total of ten questions
2. Answer all question in this paper
3. All writing must be in blue or black ink except drawing which must be in pencil
4. Write your examination number at the top right corner of every page
5. The following atomic masses may be used H=1, N=14, O=16, S=32, Ca= 40

SECTION A (marks 15)

1. For each of the items number i-x choose the correct answer from the given alternatives and write its letter in the box provided

i) Form two students discovered that it is impossible to light fire in a vacuum due to the absence of certain gas. What gas do you think is missing?

1. Nitrogen
2. Carbon dioxide
3. Oxygen
4. Hydrogen
5. Sulphur dioxide is missing

ii A simple proof that some chemical reactions take place in our bodied is that

1. We eat a balanced diet
2. Doctor tell us so in the hospital
3. We occasionally fall sick
4. The food and drinks we take are quite different from the waste product from our bodies
5. There is no proof

iii) Why oxygen as one of the components of air is unique?

1. It forms largest part of the air
2. It is diatomic gas
3. It has the largest density
4. It supports combustion
5. It does not support combustion

iv) What change of state is involved when drying wet clothes

1. Gas to solid
2. Liquid to gas
3. Gas to liquid
4. Solid to gas
5. Liquid to solid

v) Oxygen gas can be produced at a large scale by

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

vi)Which is the suitable alternative heat sources to be used inabsence of Bunsen burner?

1. Kerosene stove and torch
2. Torch and spirit burner
3. Kerosene, stove, and spirit burner
4. Fire wood and torch
5. Torch and candle

vii) In water purification using commercial filter hasthe sequence

1. Gravel, sand, charcoal, cloth and beaker
2. Gravel, sand, charcoal, beaker and cloth
3. Sand, gravel, charcoal, gravel, beaker and cloth
4. Sand, charcoal, gravel, beaker and cloth
5. Sand, beaker cloth,charcoal and gravel

viii)Sodium is abbreviated as Na but both letters are exclusive in the word sodium, thisis because

1. The Latinized as naterite
2. Comes from the word natural
3. The Latin name of sodium is Natrium
4. It is derived from the two letters of its English name
5. It is derivedfrom English name

ix) Ethanol and water mixture can be separated using

1. Layer separation
2. Simple distillation
3. Evaporation
4. Filtration
5. Fractional distillation

x)fire triangle is the component required for a fire to start This is

1. Heat, fuel and energy
2. Heat, fuel and air
3. Heat, water and energy
4. Heat, ironand light
5. Heat, light and energy

2.Match 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

SECTION B (70 MARKS)

3 (a) Everybody should be familiar with the instruments and chemicals found in the first aid kit and how to use them.Give any two instruments and two chemicals found in the first aid kit and briefly explain their uses.

(b) Water is one of the basic components in the first aid kit, yetit’s not a must to be found in a kit. Explain

(c) Give two examples of apparatuses that are made up of:

(i) Porcelain /ceramic materials

(ii) Plastic materials

(iii) Glass materials

(iv) Iron materials

4 (a) briefly explain each of the following phenomena

1. A ship in sea water, rust very fast compared to a ship in fresh water
2. A glowing splint of wood is introduced into a gas jar containing oxygen gas
3. Oxygen gas reacts with non- metals
4. Hydrogen gas reacts with oxygen gas

2. A form two students dipped a clean iron rod into a cold distilled water in a test tube and left it for 2 days, explain observation after two days.

9. State what will happens to the iron rod after 2 days?

2. Outline three things which cause the process in (b) (i) above
3. How could these students prevent the process above despite of the conditions stated. Give two methods.

5 (a) Anisha cuts on her fingers when she was preparing vegetable for lunch, immediately Vasterhelped her before she sends her to Annawema, a doctor.

(i)What was done by Vaster to Anisha?

(ii) Is the help given by Vaster to Anisha important or nothing? State four reasons to support your answer

(b) Explain briefly the following terms

(i) Melting

(ii) Freezing

(c) What are the three importance of changing states of matter from one state to another.

6 (a) Classify the following processes into physical and chemical change.

1. Boiling of water to form vapour
2. Decaying of teeth
3. Rusting of iron
4. Magnetization of iron.
5. Souring of milk
6. Grinding of chalk
7. Melting of ice.

(b) Why some processes in (a) above are classified as physical change? Give three points.

7. (a) What do you understand by the word fire?

(b)Albertina burnt a piece of wood and the results were energy and light.

(i) Name the chemical reaction involved.

(ii) What is the name given to a piece of wood in this reaction?

(iii) With one example write three areas where chemical reactions in (b )(i) above is applied.

8. The laboratory technician planned to conduct an experiment for the preparation of gas M. He decided to use hydrogen peroxide to prepare gas M.

(a) Identify gas M.

(b) Mention six apparatus he can use to prepare gas M.

(c) Write the word equation for the laboratory preparation of gas M.

(d) State two uses of gas M.

9 (a) write the Dalton’s Atomic theory that lead to the following modern atomic theory.

1. Atoms are made up of smaller particles called PRPTONS, ELECTRONS, and NEUTRONS.
2. Atom can be CREATED or DESTROYED or SPLT up by nuclear reactions.

(b) Give three reasons to why charcoal is still being used by majority of Tanzanians for domestic purpose.

(c) Draw and write electronic configuration of the following elements

1. Sodium
2. Sulphur.

SECTION C (15) MARKS

10. (a) Scientific procedures are steps used by scientists when finding answers to scientific problems. Write the steps which correspond to each of the following.

1. Kelvinia was not feeling well. Shewent to see a medical doctor at Malangali Health Center.
2. The Doctor asked Kelvinia several questions about how she was feeling.
3. The Doctor ordered Kelvinia’s body temperature, blood and urine sample for observation in the laboratory.
4. The laboratory technician diagnosed Malaria parasite in Kelvinia’s blood.
5. The doctor confirmed that Kelvinia had Malaria and prescribed medicine for her.

(b) Why is scientific procedure important? Give two points

(c) State three areas where scientific procedures are applied

TANZANIA HEADS OF ISLAMIC SCHOOLS COUNCIL

FORM TWO INTER ISLAMIC MOCK EXAMINATION

CHEMISTRY

TIME: 2:30 Hours Thursday 27^th July, 2023 p.m.

Instructions

1. This paper consists of sections A, B and C.
2. Answer all questions in the spaces provided.
3. Read carefully the instructions given in each section before answering the questions.
4. All writings must be in blue or black ink except drawings which must be in pencil.
5. All communication devices and calculators are not allowed in the examination room.
6. Write your Candidate Number on the top right on every page.
7. The following atomic masses may be used:

• H=1, C=12, O=16, N=14, S=32, Zn=65, Cl=35.5, Cu=64

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 box provided.

(i) Form one students went to the laboratory to measure fixed volume of distilled water. Which apparatus can they use?

1. Beaker
2. Burette
3. Pipette
4. Measuring cylinder

(ii) Which one of the following state of matter its volume expands indefinitely to occupy the space?

1. Liquid
2. Solid
3. Gas
4. Solution

(iii) Different gases composing Air are present in various proportions by volume. Which among the following gases its percentage in Air is not constant and varies depending on various factors?

1. Nitrogen
2. Oxygen
3. Noble gases
4. Water vapour

(iv) What happens to an atom when it becomes an ion with a charge of +1?

1. It gains an electron
2. It loses an electron
3. It gains a proton
4. It loses a proton

(v) Musa and Juma were debating about the general group trends of properties of an element in the periodic table. What trend will you recommend to them?

1. Electronegativity increases down
2. Densities decrease downward
3. Melting point decreases downward
4. Ionization energy increases downward table

(vi) Form two students were arguing about the electronic configuration of magnesium ion. Which among the following will you suggest to them?

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

(vii) Mr. Mwaisa coated the roofs of his house with zinc in order to protect it from rusting. What was the process done by Mr. Mwaisa?

1. Painting
2. Galvanization
3. Oiling
4. Alloying

(viii) Which changes of state of matter take place when the temperature of a substance is lowered?

1. Boiling and melting
2. Condensation, freezing and melting
3. Condensation and freezing
4. Melting only

(ix) The teacher was demonstrating the number of electrons a Nitrogen has to lose or gain when forming Ammonium ion. What will probably be the number?

1. +3
2. -3
3. ⁺4
4.  ^-4

(x) Which method is used to separate a mixture of the following liquids?

1. Crystallization
2. Evaporation
3. Filtration
4. Fractional distillation

2. Match the uses of Hydrogen gas in LIST A with the corresponding properties in LIST B by writing the letter of the correct response beside the item number.

ANSWERS:

SECTION B (70 Marks)

Answer all questions in this section

3. (a) Some of the elements have their symbols completely different from their common English names.

(i) Where are their symbols derived from? _______________________________

(ii) List any four (4) elements of this kind

(b) The teacher told Anna to list two elements which she knows. Anna wrote Al and O.

Why did she use a letter instead of writing their full names? Give two (2) reasons.

(i) _______________________________________________________________

(ii) _______________________________________________________________

(c) Form one students were arguing that solutions and suspension have the same appearance. Were they correct? Give two (2) reasons.

(i) _______________________________________________________________

_______________________________________________________________

(ii) _______________________________________________________________

_______________________________________________________________

4. (a) Mr. Mjatanga was preparing food for his son using hot oils on a frying pan. Accidentally, the pan toppled over and a huge fire spread on the kitchen floor.

(i) Which fire extinguisher would be suitable for putting out the fire?

_______________________________________________________________ _______________________________________________________________

(ii) Why water would not be suitable for putting off the fire stated in 4(a) above?

_______________________________________________________________ _______________________________________________________________

(b) Give reasons to support each of the following statements:

(i) Commodities like hand bags and camera bags for sale are packed with Silical gel.

_______________________________________________________________

_______________________________________________________________

(ii) When iron sheets exposed to wet air for a longtime, they turn to reddish brown in colour

_______________________________________________________________

(iii) If the clothes worn by your friend catch fire, cover them with a fire blanket

_______________________________________________________________

_______________________________________________________________

5. (a) Elements T and Q have atomic number 12 and 17, respectively. Use the two elements to answer the following questions:

(i) Write the electronic configuration of element Q.

(ii) What is the valency of element T?

(iii) Write the chemical formula of a compound formed when T and Q combine _

(iv) Mention the type of the bond formed by the combination of element T and Q.

(v) In which group and period in the periodic table does element Q belong?

_______________________________________________________________

_______________________________________________________________

(b) The orange and yellow colour of Cr₂ and CrO₄^2 respectively are determined by the number of electrons lost by the chromium. Determine these numbers of electrons lost by chromium ion in each radical.

6. (a) The laboratory technician planned to label warming signs on the containers found in the laboratory. Suggest the name of warming sign he could label on the containers containing the following:

(i) Rat poison ______________________________________________________

(ii) Methylated spirit ________________________________________________

(iii) Hydrogen peroxide _______________________________________________

(iv) Concentration sulphuric acid _______________________________________

(v) Cooking gas ____________________________________________________

(b) Adil was hit on his head by Yassir in a football game between their classes. Adil lost consciousness and fainted. Being an expert, which steps you would follow to help him before taken to hospital. (Give five points)

(i) _______________________________________________________________

(ii) _______________________________________________________________

(iii) _______________________________________________________________

(iv) _______________________________________________________________

(v) _______________________________________________________________

7. A student went to the Chemistry laboratory and found reagents and apparatuses on top of the beach. List of apparatuses

(i) Thistle funnel with cork

(ii) Round bottomed flask

(iii) Delivery tube

(iv) Water trough

(v) Gas jar

(vi) Beehive shelf

(vii) Stoppers

Reagents

(i) Hydrogen peroxide

(ii) Manganese (IV) oxide

(iii) Water

He developed an idea on the laboratory preparation of gases

(a) What is the gas that is likely to be prepared using the laboratory reagents and apparatuses shown above?

_____________________________________________________________________

(b) Write a well-balanced formula equation for the reaction involved in the preparation of the gas above?

_____________________________________________________________________

(c) What are the function of manganese (IV) oxide in the preparation of the gas named above?

_____________________________________________________________________

(d) With the aid of diagram show the laboratory set up for preparation of the gas named above.

(e) State the chemical test to identify the gas prepared above.

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

8. (a) At Magoza village, most of societies are using firewood and charcoal as a source of fuel for domestic use. Give three (3) reasons, why the villagers prefer to use such types of fuel?

(i) _______________________________________________________________

(ii) _______________________________________________________________

(iii) _______________________________________________________________

(b) Assess three (3) effects of using such fuels by villagers at Magoza village to the environment.

(i) _______________________________________________________________

(ii) _______________________________________________________________

(iii) _______________________________________________________________

(c) “Energy can neither be created nor destroyed, but it can be transformed from one form to another.” Which forms of energy can be transformed on the following conditions?

(i) Plants carrying photosynthesis process

_______________________________________________________________

_______________________________________________________________

(ii) Boiling water using gas cooker

_______________________________________________________________

_______________________________________________________________

(iii) Production of electricity using radioactive materials

_______________________________________________________________

_______________________________________________________________

(iv) Switching on a bulb

_______________________________________________________________

_______________________________________________________________

9. (a) Compound Q composed of 15.8% carbon and the rest is Sulphur. If the vapour density of compound Q is 38;

(i) Find the percentage of Sulphur in a compound Q.

(ii) Calculate the empirical formula of the compound Q.

(iii) Calculate the molecular formula of the compound Q.

(b) You are provided with the following chemical formulas CO₂, CH₄, C₂H₆ and NH₃. Categorize the given formulas as empirical and molecular formulas.

SECTION C (15 Marks)

Answer question ten (10)

10. (a) (i) Solid, liquid and gas are the three states of matter that happen exchangeably. Identify one important factor that govern changes among them.

_______________________________________________________________

_______________________________________________________________

(ii) State at least one method of separating mixture that can be useful to obtain one of the following substances:

1. Kerosene mixed with water _____________________________________

____________________________________________________________

2. Iodine from sand ______________________________________________ ____________________________________________________________

3. Ethanol from water ____________________________________________

____________________________________________________________

4. Cooking sunflower oil from sunflower seeds _______________________

____________________________________________________________

(b) Life without changes of state of matter could be almost impossible. Defend this fact by giving five (5) points.

(i) _______________________________________________________________

_______________________________________________________________

(ii) _______________________________________________________________

_______________________________________________________________

(iii) _______________________________________________________________

_______________________________________________________________

(iv) _______________________________________________________________

_______________________________________________________________

(v) _______________________________________________________________

_______________________________________________________________

(c) Identify the following properties of flames into luminous flame and non-luminous flame in the following:

PRESIDENT'S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

KILIMANJARO REGION MOCK FORM TWO EXAMINATION

 CODE:032 CHEMISTRY

TIME: 2:30 HOURS MAY 2023

INSTRUCTIONS

1. This paper consists of section A and B with total of ten (10) questions.
2. Answer all questions in the space provided.
3. Section A and C carry Fifteen (15) marks each and section B carries Seventy (70) marks.
4. All Writing Must be in black or blue ink except diagrams which must be in pencil.
5. Any unauthorized Materials are not allowed in the examination room.
6. Write your name at the top right corner of every page.

SECTION A (15 MA R KS)

Answer all questions in this section

l . For each of the items (i-x) choose the correct answer among the given alternative and write its letter in the box provided.

(i) Which term describes a rapid chemical reaction that release energy in the form of heat and light

1. Ignition 
2. combustion
3. Heating
4. Flame

(ii) The unburnt region of the non-lunlinous flame is . . . . . . . in colour

1. Colourless 
2. Black
3. Pale blue 
4. Green

(iii) Why hydrogen is not a constituted of air?

1. Because of being highly flammable
2. Because of being a reducing agent
3. Because of being very light
4. Because of being very reactive

(iv) Which of the following warning signs is likely to appear on the bottle containing concentrated Nitric acid in the laboratory?

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

(v) How can one prevent rusting in fragile instrument like camera?

1. By using silica gel
2. By using ethanol
3. By galvanization
4. By using oil

(vi) The teacher was demonstrating an experiment by dissolving sodium chloride in water until the solute was not dissolving any more. What type of' solution was formed at the end of experiment

1. Saturated 
2. Unsaturated
3. Suspension 
4. Super saturated

(vii) What does the random movement of grains suspended in air demonstrates?

1. Matter is solid in nature
2. Matter is solid, liquid or gas in nature
3. Matter is Particulate in nature
4. Matter is gaseous in nature

(viii) A chemist observed that when iron nail is left overnight the nail rust. He later said that this was due to presence of moisture in the atmosphere during the night. This can be termed as:

1. Hypothesis
2. Observation
3. An interpretation
4. Conclusion

(ix) Which of the following are the products of the reaction of sodium with water?

1. Sodium oxide and hydrogen gas
2. Sodium oxide and water vapour
3. Sodium hydroxide and hydrogen gas
4. Sodium hydroxide and water vapour

(x) Which of the following electronic configurations are of metal?

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

2. Match each item in list A with correct response in list B by writing the letter of' the correct response below the corresponding item number in the letter provided'

ANSWERS

SECTION B (70 Marks)

Answer all questions in this section

3. (a) Chemistry plays great role in our world. Its knowledge and skills applied when solving daily life problems related to food, water, soil. health. energy, shelter, clothing, and clean air. Justify this fact by giving five importance of studying chemistry.

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

(b) Explain live areas where chemistry is applied.

4. (a) One of the significant of chemical symbols is to distinguish one element from the other and quickly understand the elements being referred to assign chemical symbol for each of the following elements.

(b) Differentiate luminous flame from non-luminous flame by giving five points.

5. Study the periodic table for the first 20 elements below

Use the letters shown in the periodic table above to indicate:

1. The lightest atom 
2. An alkaline earth metals 
3. A halogen 
4. Element with O valence, used to fill weather balloons
5. Write the electronic configuration of J
6. Give the names of A and F 
7. Write the chemical formula when H combine with F

6. (a) Fuels may be classified on the basis of their physical state with one example, give the three main states Fuels.

1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) There is a close relationship between some physical properties of water and usefulness. State two main physical properties of water and their usefulness.

1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7. Halima needed to measure the volume of water in the chemistry laboratory. Which apparatuses should be used.(three apparatuses)

1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) Name three apparatuses that are made by ceramic materials

1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c) During practical activities in the laboratory several accidents could occur. Mention four accidents that needs first aid procedures

1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8. (a) By giving a reason, suggest the suitable method of separating each of the following

(b) Briefly explain each of the following phenomena

1. A black copper (iii) oxide changed to brown colour when combine with hydrogen gas
2. A bottle fully of water burst when exposed in a deep freezer overnight

9. (a) Assign each of the following changes to either a physical change or a chemical change by putting a tick on the respective column in the following table.

b) If a sample X consists of 99.76% of ¹⁶X, 0.04% of ¹⁷X and 0.3% of ¹⁸X

1. Calculate the relative atomic mass of x.
2. Identify the element X.

SECTION C (15 Marks)

Answer question 10

10. (a) A chemistry teacher wants to demonstrate the laboratory preparation of oxygen by decomposition method. He appointed a form two students to collect apparatus for this experiment.

1. List all apparatus for this experiment above.
2. State two reagents for the laboratory preparation of' oxygen by decomposition.

(b) Write a word equation for the reaction between two reagents above.

(c) State five physical properties of the gas produced above.

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

LUDEWA DISTRICT COUNCIL

FORM TWO MOCK EXAMINATION 2022

032 CHEMISTRY

TIME: 2:30 Hours 8th JUNE 2022

INSTRUCTIONS

i. This paper consists of section A, B and C

ii. Answer All questions in all sections

iii. Calculators and cellular phone are Not allowed in examination room

iv. Write your number on every page on every page on space provided

v. Constants used;-

H=1, C=12, O=16, Ca=40, Cl=35.5, K=39 ,Na=23 , N=14

SECTION A (15 Marks)

Answer all questions from this section

1. From item (i-x), choose the correct item from the given alternatives and write its answer beside the item number provided.

i. A form two student was preparing different types of mixtures in the chemistry laboratory. The first mixture, he dissolved 30grams of sodium chloride crystals (NaCl) in 500cm3 of water then he stirred the mixture for about five minutes. What is the name of this mixture prepared by a student?

1. Heterogeneous mixture
2. Suspension mixture
3. Colloidal mixture
4. Homogenous mixture

ii. One student from form one observed that most of the kitchen tools such as plates, cups, bowl and jugs are made of steel which is smooth and shiny. As a chemistry student why these kitchen tools are made up by such steel?

1. To make them look expensive
2. To make them shiny
3. To prevent them from rusting
4. To make easy to see

iii. Kimbe was doing experiment concerning flame test of different chemical substances in the chemistry laboratory, unfortunately his laboratory coat caught fire .Which of the following fire extinguishing items will you use to help him to extinguish fire from his laboratory coat?

1. Fire blanket
2. Carbon dioxide
3. Water
4. Form

iv. An element H with valency of 2 react with another element L with valency of 3. What is the probable chemical formula between atoms of element H and element L?

1. H₂L₃
2. L₂H₃
3. H₃L₂
4. HL₂

v. Jackline when was mopping chemistry laboratory she saw a sign of cross on a plastic bottle containing a certain chemical. Which of the following is the correct answer about the interpretation made by Jackline concerning the property of chemical contained in the bottle?

1. Radioactive
2. Harmful
3. Toxic
4. Oxidant

vi. Form four students in a certain school were conducting experiment about volumetric analysis. In their experiment they were required to transfer three drops of methyl orange from the reagent bottles into the reacting vessels. Do you think which of the following apparatus they were using to transfer three drops of methyl orange from reagent bottle to reacting vessels?

1. Beaker
2. Burette
3. Spatula
4. Dropper

vii. Students from Lugarawa health training center were doing a scientific research about malaria in Njombe region. Which among the following scientific procedures they were using to accept or to reject their hypothesis made?

1. Conclusion
2. Data interpretation
3. Data analysis
4. Experimentation

viii. During the practical session one student mixed accidentally the iron fillings with sulphur powder. Assume you are the expert of chemistry which method will you use to obtain these two components of the mixture separately?

1. Piking
2. Filtration
3. Magnetization
4. Evaporation

ix. Boron is known to have two stable isotopes of atomic masses 10.016g and 11.013g. The isotopes normally exists in nature in the proportions of 20% and 80%respectively, from the data what is the average mass of Boron?

1. 10.81g
2. 10.62g
3. 10.51g
4. 10.58g

x. Laboratory technician wanted to know the liquid present in beaker labeled L left after experiment. He took two drops of liquid L and he decided to add it into petri dish containing white anhydrous copper (II) Sulphate crystals. Immediately after the addition of three drops of liquid L into petri dish containing the anhydrous copper (II) Sulphate crystals the mixture turned to blue colour. What is the name of liquid present in beaker labeled L?

1. Water
2. Acid
3. Salts
4. Base

ANSWERS

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.

ANSWERS

3. a) Most of farmers in the rural areas were interested to know how the knowledge of chemistry is necessary in agricultural activities. Assume you are a chemist; educate these farmers on the application of chemistry in agriculture by giving five points.

b) The headmaster of a certain school was bought a small box which had a sign of Red Cross. Most of form one students they did not have a knowledge about that box.by using knowledge that you have learnt from chemistry answer the following questions.

i. What is the name given to that box

ii. Briefly explain the functions of four possible items that can be found in a box

4. a) A laboratory technician advised students to use non-luminous flame when they are heating chemicals in the laboratory. As a form two student explain briefly four reasons why he encouraged students to use this kind flame?

b) Some people in the society believe that solving problems by using scientific procedure is the wastage of time and money. By using knowledge of chemistry that you have refute the statement by giving four points.

5. a) Assume you are given two gas jars, one gas jar containing gas A and another gas jar containing gas B. Gas A is used to fill balloons while gas be is used to by ocean deep divers.

i. What are the chemical test of gas A and gas B?

Gas A . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gas B . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ii. Explain five uses of gas A in your daily life.

b) Mwahisa placed a yellow solid on a deflagrating spoon, ignited and then lowed the spoon into a gas jar of oxygen .The solid burnt vigorously with a yellow flame and finally the product was a pale yellow solid.

i. What is the name of the yellow solid that is burnt in oxygen

ii. Write the chemical formula of the pale yellow product formed

iii. Write the word equation for the reaction

6. a) During the rains many rivers fill with muddy water, which people use for drinking. This water has caused them to suffer from water borne diseases such as typhoid and diarrhea. Explain two simple methods that can be used to obtain clean water from these rivers muddy water.

b) One form one student from a certain school was given a task by her teacher to write the chemical symbols of the following elements; sodium, iron and chlorine. But the student did as shown below in 6b ( i, ii, and iii). Help him by identifying his mistakes and then write a correct symbol in each

i. Symbol of sodium is (So)

ii. Symbol of iron is (Ir)

iii. Symbol of chlorine is (CL)

7. a) A form one student from a certain school given a task by her teacher to state the type of fire extinguisher(s) that she will use to extinguish fire caused by the burning materials listed below. Unfortunately a student failed to attempt this question correctly. As a form two student help her to answer this question.

i. Burning curtain 

ii. A fire started by a short circuit in an electric iron

iii. A fire started by hot oil in a frying pan

iv. Fire started on a bucket containing sodium metal

b) Cars, motorcycles and corrugated iron sheets in coastal towns like Dar es Salaam, Tanga and Zanzibar are found to rust more quickly than in other cities in Tanzania like Songea, Njombe, Mwanza and Arusha. Why is this so?

8. a) A compound consists of 27% sodium, 16.5% nitrogen and 56.5% oxygen by mass. Calculate the simplest formula of the compound.

b) During the practical session, Asha found some bottles in the laboratory containing different chemical compounds with different chemical formulas, unfortunately she failed to write the IUPAC names of these chemical compounds. As form two student help her by writing the correct IUPAC names of these chemical compounds found by Asha on bottles in the laboratory.

i. KCl . . . . . . . . . . . . . . . . . .

ii. Na2SO₄ . . . .  . . . . . . . . . 

iii. CaCl₂ . . . . . . . . . . . . . . .

iv. AlCl₃ . . . . . . . . . . . . . . .

v. SF₆ . . . . . . . . . . . . . . . . .

9. a) Oxygen exists naturally in three different isotopes which are, ¹⁶₈O(99.76%), ¹⁷₈O(0.04%) and ¹⁸₈O(0.20%). Calculate the relative atomic mass of oxygen

b) Use the knowledge that you have complete the following table below by indicating the number of protons, electrons and neutrons of different atoms shown in the table below. The atomic number and mass number are given.

SECTION C: 15 MARKS

10. Nowadays the world is suffering from climatic changes which is caused by over dependent on forests as a source of fuels, and over production of waste materials that pollute our environment. To overcome this problem is through the use of renewable source of energy such as biogas produced from animal dungs and sewage wastes. As the expert of chemistry prepare a report to convince the community to use this gas produced by animal dungs as the alternative source of energy while they are conserving the environment.

Students Assesment Number_________________

THE PRESIDENT’S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

MOSHI MUNICIPAL COUNCIL

SECONDARY EDUCATION EXAMINATIONS SYNDICATE

032 CHEMISTRY

FORM TWO MOCK ASSESMENT

Tuesday 28th June 2022 Am Time 2:30Hours

Instructions

1. This paper Consist of sections A, B and C with total of 10 questions

2. Answer all questions in both sections

3. All writings should be in blue/black ink

4. All diagrams should be drawn in pencil

5. Write your assessment number at the top right corner

SECTION A (15Marks)

1. For each of the items (i)-(x), choose the correct answer from among the given alternative and write its letter in the box provide.

i. The welders prefers to use non luminous flame for their work simply because

1. It is available
2. it is easy to transport
3. produce very hot flame
4. can be made by kerosene

ii. Spatula in the laboratory is used for scoping what types of substances?

1. Liquid and gases 
2. solids and liquids
3. Powdery and gases 
4. Solids and powdery

iii. There are two particles inside the nucleus which one contributes the net change of that nucleus?

1. Dalton 
2. Protons
3. Electrons
4. Neutrons

iv. Why oxygen as one of the components of air Is unique?

1. It has ability to burn 
2. it support combustion
3. it is diatonic gas
4. combine with carbon dioxide

v. Why it is necessary to boil drinking water?

1. To make it tasteless 
2. To remove impurities
3. to kill micro-organism 
4. To make it taste less

vi. How do chemists refer to a mixture of milk and water?

1. Miscible solution 
2. Suspension
3. Immiscible solution 
4. Emulsion

vii. How can one prevent rusting in fragile instruments like camera?

1. By galvanization 
2. By using silica gel 
3. By using oil 
4. By using ethanol

viii. The oxidation state of metallic element is always

1. Negative 
2. Positive 
3. Zero 
4. Neutral

ix. Which of the following is not man-made product of applying chemistry?

1. Sugar 
2. Fertilizer
3. Milk
4. Vaccines

x. The atomic number of element R is 9 What is its electronic configuration?

1. 2:4:3 
2. 2:5:2
3. 2: 7 
4. 2:6:1

ANSWERS

2. (a) Match each item in List A with a correct response in List B by writing the letter of the correct response below the corresponding item number in the table provided

ANSWERS

SECTION B: (70MARKS)

3. (a) Mrs. Msema kweli was addressing the villagers about use of water for economic values. What 4 values will she tell the villagers

(b) Is an air a mixture or a compound? Give 4 reasons

4. (a) Do your think there is any reasons for providing first Aid to the Victim? If yes give four reasons.

(b)State the uses of the following items in first aid Kit.

i. The pair of scissors

ii. The whistle 

iii. Petroleum Jelly 

iv.Sterile gauze

5. (a)State three sub- atomic particles and their respective charge.

(b)State the four modification of Dalton`s atomic theory

(c)Draw and write the electronic configuration for the atoms having the following atomic numbers.

(i) 4Be 

(ii)14Si

6. (a)Distinguish the following substances.

i. Homogenous mixture from heterogeneous mixture.

ii.Miscible from immiscible liquids.

iii. Saturated from unsaturated solution.

(b)Give two chemical tests for pure water

7. (a)Asha want to select a good fuel for domestic uses in her home what things should she considered? (Mention six (6)

(b)Classify the following fuel either primary or secondary fuel.

(i) Coke 

(ii)Crude oil

(iii)Kerosene

(iv)Natural gas 

8. (a)What properties of hydrogen gas that made it to be used in the following?

i. As a fuel 

ii. To fill weather balloons 

iii. Manufacture of hydrochloric acid

iv. Manufacture of margarine 

(b) Environmental pollution in most of rural areas in Tanzania is caused by using charcoal and firewood as a fuel. What will be the two alternative source of energy, they supposed to use for environmental conservation? (give reason for each)

(c) Why fossil fuels are referred to as non-renewable energy resources? (Give two reasons)

9. (a)You are provided with the following atoms, for each fill the informations below:-

(i) ^35.5Cl

protons = 

Neutrons=

Electrons=

(ii) ¹H

protons = 

Neutrons= 

Electrons=

(b) Define the following

i.Atom

ii. Energy

iii.Atomic number

v. Isotopes

SECTION C (15 MARKS)

10a)i. What do you understand by the word “Relative atomic mass”?

ii). Carbon has main isotopes,¹²₆C and ¹⁴₆C with relative abundances 98.89% and1.11% respectively. Calculate the relative atomic mass of Carbon.

b)i. Draw a diagram of laboratory preparation of oxygen gas from hydrogen peroxide and manganese IV oxide

(ii) Write the word equation for the reaction above (a)i

c) Answer the following questions with reference to the first 20 elements of the periodic table

i. Give the chemical symbol of element having:

• The smallest atomic size______________________________________________

• The largest atomic size _______________________________________________

ii.Identify the element which are:

• Metals having three shells of electrons each

• Metals having 1 electron in the valence shell

• Noble gases ___________________________________________________________

PRESIDENT’S OFFICE REGIONAL ADMINISTRATIVE AND LOCAL GOVERNMENT

TANZANIA HEADS OF ISLAMIC SCHOOLS COUNCIL

FORM TWO INTER ISLAMIC MOCK EXAMINATION

 032 CHEMISTRY  

TIME: 2:30 HOURS Monday, 27^th September 2021 p.m.

Instructions

1. This paper consists of sections A and B with a total of ten (10) questions.

2. Answer all questions in the spaces provided.

3. All writings must be in blue or black ink except drawings which must be in pencil.

4. All communication devices and calculators are not allowed in the examination room.

5. Write Your Examination Number on the top right of every page.

6. The following atomic masses may be used.

H = 1, C = 12, O = 16, N = 14, S = 32, Zn = 65, Cl = 35.5, Na = 23.

SECTION A: (20 Marks)

1. Write down the letter corresponding to the most correct answer in the box provided for each item.

(i) How many protons, neutrons and electrons are there in an atom represented by ?

(ii) Which of the following methods is used to separate salt from sea water?

1. Filtration
2. Decantation
3. Decantation
4. Fractional distillation.

(iii)Which of the following warning signs is likely to appear on a gallon containing methylated spirit in the laboratory?

1. Irritant
2. Flammable
3. Oxidant 
4. Explosion.

(iv) Hydrogen peroxide (iv) X + water. “X” represents _________

1. Oxygen
2. Hydrogen
3. Nitrogen 
4. Carbondioxide.

(v) If a Bunsen burner produces much soot, which is the correct conclusion?

1. The air hole is closed
2. The burner gas jet is big
3. The air hole is fully opened
4. The gas supply is poor.

(vi) Which of the following is the list of group (II) element?

1. Sodium and magnesium
2. Calcium and carbon
3. Magnesium and calcium
4. Boron and Beryllium.

(vii) Element M of group I combines with element X of group VI, the formula of the compound formed when M combines with X is:

1. MX₂
2. MX₆
3. X₂m
4. M₂X.

(viii) The pair of elements which is most likely to form a covalent bond when reacted together is:

1. Carbon and chlorine
2. Aluminium and oxygen
3. Magnesium and oxygen
4. Sodium and chlorine.

(ix) One of the following can distinguish hydrogen gas from other gases: 

1. It burns and supports combustion
2. It is colourless and odorless 
3. It gives a smell of a rotten egg
4. It burns with pop sound.

(xi) The following sentences suggest that air is a mixture, except:

1. Its components can be separated physically
2. Its composition varies from one place to another
3. Its properties depends on individual gases
4. Its formation requires absorption or reabsorption of heat.

2. (a) Choose a word(s) from list B which matches the statement or phrases in list A and write its letter in the space provided.

Answer:

2. (b) Fill in the blanks below with the correct words.

(i) A candle flame is not good for glass ware because _____________________

(ii) A catalyst used for the production of oxygen gas from hydrogen peroxide is _______________________

(iii) A sudden unexpected occurrence that destroy properties and cause injury is called __________________________

(iv) It is used as fuel in rockets due to its lightness _________________________

(v) Blockage of the upper part of airway by food or other objects is called ________________________________

SECTION B: (80 Marks)

Answer all questions in this section

3. (a) What is fuel?

(b) (i) State four types of fuels used by many Tanzanians:

(ii) Why do you think many Tanzanians prefer to use the mentioned sources in 3b(i) above? Give two best reasons.

4. You are provided with the following materials from chemistry laboratory:

Apparati: Thistle funnel, delivery tube, beehive self, trough, gas jar, flat bottomed flask with its coke.

Chemicals:Water, zinc granules, dilute hydrochloric acid.

(a) What chemical substance can be prepared using the materials mentioned above?

(b) Draw the diagram showing how you could arrange the Apparati above in order to prepare a chemical substance you mentioned in 4(a) above. 05 marks

(c) How can the products mentioned in 4(a) above be collected?

(d) Give at least three (3) uses of the product you mentioned in 4(a) above based on its properties.

5. (a) What should you do immediately if:

(i) The piece of broken beaker cuts your finger

(ii) Chemicals splash on your face

(iii) Your shirt has caught fire

(iv) Your fellow student swallows unknown chemical substance thinking that it was water

(b) Why do you think first aid is an important thing? Give two points:

6. (a) (i) A table salt is a common name for the compound with the formula NaCl.

Write the systematic name for the table salt

(ii) Briefly describe why molecular formula better preferred than empirical formula is

(b) A compound consists of 27% sodium, 16.5% nitrogen and 56.5% oxygen by mass. If its molecular mass is 85g, find:

(i) Its empirical formula 05 marks

(ii) Molecular formula 02 marks

7. (a) Briefly explain the following terms:

(i) Periodicity

(ii) Electronegativity

(iii) Ionization energy

(iv) Atomic radii/size.

(b) Why are certain elements in the period table referred to as metalloids? Give two examples of such elements:

Reason: ____________________________________________________________

 02 marks

Example:

(i) _____________________________________________________________

(ii) _____________________________________________________________

 @ 00 ½ mark

(c) Element X has atomic number of 19 and neutron number 20. Write down its:

(i) Electronic configuration

______________________________________________________________

 01 mark

(ii) Mass number 02 marks

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

8. (a) (i) Differentiate combustion from rusting.

_______________________________________________________________

_______________________________________________________________

(ii) Explain why cars and corrugated iron sheets in coastal areas like Dar es

Salaam, Tanga and Zanzibar get rust more quickly than in other cities of

Tanzania like Mbeya, Mwanza and Arusha? 02 marks

_______________________________________________________________

_______________________________________________________________

(b) Explain how you can put off each of the following types of fire

(i) A fire started by petrol in a container 02 marks

_______________________________________________________________

_______________________________________________________________

(ii) A fire started by a short circuit in an electric wire 02 marks

_______________________________________________________________

(iii) A fire caused by a burning magnesium metal 02 marks

_______________________________________________________________

9. (a) With an example give the meaning of the following terms as applied in Chemistry:

(i) A radical 02 marks

_______________________________________________________________

_______________________________________________________________

(ii) Oxidation state 02 marks

_______________________________________________________________ _______________________________________________________________

(b) Find the oxidation numbers of the following underlined elements:

 (i) Na 01mark 

(ii) HNO₃ 01mark

(iii) H₂SO₄  01mark 

 (iv) SO₃^2- 01mark

(c) Draw diagrams showing the electron transfer in the formation of MgCl₂.

10. (a) Differentiate the following terms:

(i) An element and an atom

(ii) A compound and a mixture

(b) Melting of ice and burning of papers are two processes that happen almost daily in our life.

(i) Identify the two actions as being physical or chemical change.

• Ice melting __________________________________________________ 
• Paper burning ________________________________________________

(ii) Mention two significant things that happen when the paper is burnt:

(c) What are the names of elements represented by the following symbols?

(i) K _________________________________________________________

(ii) S _________________________________________________________

(d) Why some elements have their symbols written in one letter while others have two letters? (e.g. N and Na)

PRESIDENT’S OFFICE REGIONAL ADMINISTRATIVE AND LOCAL GOVERNMENT

KILOSA DISTRICT COUNCIL

 FORM TWO TERMINAL EXAMINATION

CODE: 032 CHEMISTRY

TIME: 2.30Hours. Tuesday August 25, 2020. 

Instructions

• This paper consists section A and B with a total of ten (10) questions

• Answer all questions in the spaces provided.

• All writing must be in black or blue ink except diagrams which must be in pencil.

• The following atomic masses may be used: N= 14, C= 12, H= 1, S= 32, O= 16, Cu= 63,Cl=35.5

SECTION A (20 MARKS)

Answer all questions in this section

1.This section consists of multiple choice items (i)-(x).Write down the letter of the most correct response for each question:

(i) Chemistry is one of the sciences which deals with:

1. The study of body cells 
2. Composition,properties and behavior of matter 
3. Chemical changes 
4. Physical changes 

(ii) The process of chlorination in water treatment aims at:

1. Syrup making 
2. Removing bad smell 
3. Killing micro-organisms
4. Formation of suspension

(iii) The atomic number of an element is the:

1. Number of protons 
2. Mass number  
3. Number of neutrons
4. Number of protons and neutrons

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

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

(v) Coloured substances can be separated through the process called:

1. Distillation 
2. Sublimation 
3. Filtration
4. Chromatography

(vi) When you melt a piece of iron ,it undergoes:

1. Combination 
2. Physical change 
3. Chemical change 
4. Sublimation 

(vii)When element R of Group I combines with element F of Group VI, the formula of compound formed is:

1. R₂F 
2. F₂R 
3. RF₂ 
4. RF

(viii) The apparatus which used to measure a fixed volume of 20cm³ or 25cm³ in the laboratory.

1. Measuring cylinder 
2. Beaker 
3. Burette 
4. Pipette 

(ix) The electronic configuration of sulphur is :

1. 2:8:6 
2. 2:8 
3. 2:7 
4. 2:8:5

(x) When oxygen combines with metals they:

1. Form properties 
2. Water 
3. form metallic oxides 
4. Rust

2.(a) Match each item in List A with a correct response in List B by writing its letter below the number of the corresponding item in the table provided.

(b). Fill in the blanks with the correct answer.

(i) ………………Involves covering of iron with zinc layer by dipping in molten zinc.

(ii) A bond formed by electron sharing………………

(iii) …………… is a substance which cannot be split into two or more simpler substance by any chemical means.

(iv) Matter is made up of very tiny particles called ................................ 

(v) .......................supports the bunsen burner making it stable.

SECTION B (80 MARKS)

Answer All question in this section

3. (a) Define the following terms

(i) Compound

(ii) Mixture

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

(i) Liquid to Gas is...............................

(ii) Solid to Liquid is .........................

(iii) Gas to Liquid is ............................

(c). Give three difference between muddy water and carbondioxide

4. Study the diagram carefully and then answer the questions that follows.

(a) (i) Name the apparatus labelled B, C, D and G.

B……………….................................................................

C………………………………………………………….

D………………………………………………..................

G……………………………………………………..……

(ii) Name the gas E ………………………………………………….

(iii) What is the test of gas E ………………………………………

(iv) Give the function of each of the following

A…………………………………………………………………

F…………………………………………………………………

(b) Give the reason to why hydrogen is used in

(i) Manufacture of margarine……………………………………….

(ii) Filling Weather balloons………………………………………

5. (a) Define the term fuel..........................................................................

……………………………………………………..……………………

(b) 2210KJ was liberated when 0.05Kg of a biodiesel was heated. Calculate the energy value of the fuel (biodiesel).

6. (a) Write the chemical formula for each of the following compound

(i) Dinitrogen trioxide 

(ii) Aluminium oxide 

(iii) Iron(iii) cloride 

(iv) Nitric(v) acid 

(c) Give the IUPAC system name of the following chemical compounds:

(i)HClO₃………………………………………………

(ii) CuO………………………………………………..

(iii) P₂O₅………………………………………………

(c)Draw and give function of the following apparatuses:

7. (a) Give the meaning of the following;

(i) Radical

(ii) Valence

(iii) Oxidation number

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

8. (a) Most of laboratory apparatuses are made up of glass materials. Why? (Give three reasons)

(b) Briefly explain how to handle chemicals having the following warning signs.

(i) Flammable

(ii) Corrosive

(c) Why luminous flame produces soot?

9. (a) Mr. Shing’weng’we took two beakers containing water and labeled the as beaker A and beaker B. He put one spoon of chalk powder in beaker A then he stirred to mix it and in beaker B he put one spoon of sugar and stirred to mix it. Give three differences between the mixture in beaker A and the mixture in beaker B.

(b) Name three different kinds of natural water:

(c) State three(3) uses of water in economic activities:

10.(a) Define the following terms:

(i) Empirical formula

(ii) Molecular formula

(b) A certain compound has a molecular mass of 60g and has the following percentage composition by weight: carbon 40%, hydrogen 6.67% and oxygen 53.3%. Calculate 

(i)The simplest formula of the compound:

(ii) The molecular formula