Match the physical processes represented by arrows (i) - (v) in List A with the corresponding terms in List B by writing the letter of the correct response beside the item number in the answer booklet provided.
List A
List B
(i)
A Freezing
(ii)
B Condensation
(iii)
C Deposition
(iv)
D Sublimation
(v)
E Melting
F Evaporation
G Conversion
(i)
Which process is represented by arrow (i)?
1 mk
(ii)
Which process is represented by arrow (ii)?
1 mk
(iii)
Which process is represented by arrow (iii)?
1 mk
(iv)
Which process is represented by arrow (iv)?
1 mk
(v)
Which process is represented by arrow (v)?
1 mk
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101.1 mark
Which of the following pairs constitute the best methods for treating and purifying water?
A.Chlorination and aeration
B.Chlorination and decantation
C.Chlorination and filtration
D.Chlorination and sedimentation
E.Chlorination and distillation
102.1 mark
A good fuel is the one which has
A.high speed of continuous energy supply.
B.high energy value supplied
C.low carbon dioxide supplied
D.high carbon dioxide production.
E.high content of non-combustible material.
103.1 mark
A rapid chemical reaction that releases energy in form of light and heat is called
A.combustion.
B.decomposition.
C.displacement.
D.neutralization.
E.precipitation.
104.1 mark
Which one is the molecular formula for prop-1-yne?
A.C$_3$H$_6$
B.CH$_3$CCH$_3$
C.C$_3$H$_4$
D.HCH$_2$CCH$_2$
E.CH$_3$CHCH$_3$
105.1 mark
Which of the following is not a component of the First Aid Kit?
A.Goggles
B.A pair of scissors
C.Dropper
D.Gloves
E.Razor blade
106.1 mark
Which of the following is the correct sequence of the last two steps you should follow during the scientific procedure?
A.Hypothesis formulation and conclusion
B.Observation and problem identification
C.Experimentation and conclusion
D.Problem identification and hypothesis formulation
E.Interpretation of data and conclusion.
Section B
3.7 marks
3. (a) Giving an example for each, give four uses of matter in daily life.
(b) Why are chemical symbols useful in Chemistry? Give three reasons.
(a)
Giving an example for each, give four uses of matter in daily life.
4 mk
(a)
Giving an example for each, give four uses of matter in daily life.
0 mk
(b)
Why are chemical symbols useful in Chemistry? Give three reasons.
3 mk
(b)
Why are chemical symbols useful in Chemistry? Give three reasons.
0 mk
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4.7 marks
4. (a) Give four laboratory apparatuses that are made up of porcelain/ceramic material.
(b) Outline three steps of administering First Aid to a person having a bruise on his leg resulting from a fist/hand blow.
(a)
Give four laboratory apparatuses that are made up of porcelain/ceramic material.
4 mk
(a)
Give four laboratory apparatuses that are made up of porcelain/ceramic material.
0 mk
(b)
Outline three steps of administering First Aid to a person having a bruise on his leg resulting from a fist/hand blow.
3 mk
(b)
Outline three steps of administering First Aid to a person having a bruise on his leg resulting from a fist/hand blow.
0 mk
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5.7 marks
5. (a) What is the molarity of a solution containing 10% by mass of calcium hydroxide in 0.5 dm⁻³ of solution?
(b) 25 cm³ of a molar solution of sodium hydroxide is diluted to 85 cm³. Calculate the concentration of the solution after dilution. (Give your answer in two decimal places).
(a)
What is the molarity of a solution containing 10% by mass of calcium hydroxide in 0.5 dm3 of solution?
4 mk
(a)
What is the molarity of a solution containing 10% by mass of calcium hydroxide in 0.5 dm³ of solution?
0 mk
(b)
25 cm3 of a molar solution of sodium hydroxide is diluted to 85 cm3 . Calculate the concentration of the solution after dilution. (Give your answer in two decimal places).
3 mk
(b)
25 cm³ of a molar solution of sodium hydroxide is diluted to 85 cm³. Calculate the concentration of the solution after dilution. (Give your answer in two decimal places).
0 mk
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6.7 marks
6. (a) Briefly explain the basic steps you would follow in water treatment.
(b) Outline how to test for the purity of water.
(a)
Briefly explain the basic steps you would follow in water treatment.
4 mk
(a)
Briefly explain the basic steps you would follow in water treatment.
0 mk
(b)
Outline how to test for the purity of water.
0 mk
(b)
Outline how to test for the purity of water.
3 mk
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7.7 marks
7. (a) Briefly explain five importance of balancing chemical equations.
(b) Give a balanced chemical equation for the reaction between sodium carbonate and hydrochloric acid.
(a)
Briefly explain five importance of balancing chemical equations.
5 mk
(a)
Briefly explain five importance of balancing chemical equations.
0 mk
(b)
Give a balanced chemical equation for the reaction between sodium carbonate and hydrochloric acid.
2 mk
(b)
Give a balanced chemical equation for the reaction between sodium carbonate and hydrochloric acid.
0 mk
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8.7 marks
8. (a) Calculate the concentration in g/dm³ of vinegar (CH₃COOH) if 25.0 cm³ of 0.1 M sodium hydroxide reacts with 12.5 cm³ of vinegar.
(b) By giving a reason, suggest the suitable indicator for the reaction in 8(a) above.
(a)
Calculate the concentration in g/dm3 of vinegar (CH COOH) if 25.0 cm3 of 0.1 M sodium hydroxide reacts with 12.5 cm3 of vinegar.
5 mk
(a)
Calculate the concentration in g/dm³ of vinegar (CH₃COOH) if 25.0 cm³ of 0.1 M sodium hydroxide reacts with 12.5 cm³ of vinegar.
0 mk
(b)
By giving a reason, suggest the suitable indicator for the reaction in 8(a) above.
2 mk
(b)
By giving a reason, suggest the suitable indicator for the reaction in 8(a) above.
0 mk
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9.7 marks
9. A Form Three student conducted an experiment to prepare a gas in the laboratory by decomposing a certain compound using electricity. She allowed a steady electric current to flow through the solution for 3 hours at s.t.p. If the volume the gas obtained was 4.12 dm³ and the gas relighted a glowing splint;
(a) name the gas that was produced.
(b) calculate the electric current that was flowing in the solution.
(a)
name the gas that was produced.
2 mk
(a)
name the gas that was produced.
0 mk
(b)
calculate the electric current that was flowing in the solution.
5 mk
(b)
calculate the electric current that was flowing in the solution.
0 mk
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10.7 marks
10. (a) Draw diagrams to show the atomic structures of the elements with atomic number 1, 10, 16 and 19.
(none)
Draw diagrams to show the atomic structures of the elements with atomic number 1, 10, 16 and 19.
7 mk
(a)
Draw diagrams to show the atomic structures of the elements with atomic number 1, 10, 16 and 19.
0 mk
(b)
Element X has 20 electrons and a mass number of 40. Work out the number of each type of nucleons present.
3 mk
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11.7 marks
A certain compound having a relative molecular mass of 76 was found to contain 15.8% of carbon and 84.2% of sulphur. Based on this information:
(a)
determine the empirical formula and molecular formula of the compound.
1 mk
(b)
give the IUPAC name of the compound.
1 mk
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12.7 marks
Ammonia gas is manufactured by reacting nitrogen gas with hydrogen gas in the presence of a catalyst. Write a balanced chemical equation for the reaction and explain the role played by the catalyst in this reaction.
The following figure shows the reaction path between sodium hydroxide and hydrochloric acid.
Giving a reason, classify the reaction based on energetics and predict the effects of cooling the system while increasing pressure at the same time.
(a)
Ammonia gas is manufactured by reacting nitrogen gas with hydrogen gas in the presence of a catalyst. Write a balanced chemical equation for the reaction and explain the role played by the catalyst in this reaction.
1 mk
(b)
Giving a reason, classify the reaction based on energetics and predict the effects of cooling the system while increasing pressure at the same time.
1 mk
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Section C
13.15 marks
Carbon is one of the elements that have allotropes. Explain how the allotropes of carbon differ from each other.
(none)
Explain how the allotropes of carbon differ from each other.
15 mk
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14.15 marks
Despite its corrosiveness, sulphuric acid is very important in industry. Explain the importance of sulphuric acid in industries by giving six points.
(none)
Explain the importance of sulphuric acid in industries by giving six points.
15 mk