THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL OF TANZANIA CERTIFICATE OF SECONDARY EDUCATION EXAMINATION
032/1 CHEMISTRY 1
(For Both School and Private Candidates)
Time: 3 Hours Thursday, 08th November 2018 a.m.
Instructions
H 1, C = 12, 0=16, N = 14, Cu = 64, Pb = 108. vogadros number = 6.02 x 1023.
GMV at s.t.p = 22.4 dm3.
1 Faraday = 96,500 coulombs.
Standard pressure = 760 mm Hg.
Standard temperature = 273 K.
1 litre = 1 dm3 = 1000 cm3.
SECTION A (20 Marks)
Answer all questions in this section.
1. For each of the items (i) (x), choose the correct answer from the given alternatives and write its letter beside the item number.
(i) Which of the following is an agricultural chemical products made by the application of chemistry?
(ii) A current of 0.2 A was passed through an electrolyte for 16 minutes and 40 seconds. What is the quantity of electricity produced in coulombs?
(iii) Substance X liberates chlorine gas from acidified potassium chloride. The behaviour of X is described as:
(iv) Which carbonate is the most stable to heat?
(v) Aluminium does not react with water and does not corrode much in air because
(vi) Which of the following compounds does NOT belong to the alkenes homologous series?
(vii) In the following equilibrium equation, 2S02(g) +O2(g) 2S03 The forward reaction is exothermic. Which change would increase the production of sulphur trioxide at equilibrium?
(viii) When a burning fuel produces blue color it means there is
(ix) Which of the following equations represents the combustion of methane with the products collected at 120oC?
(x) Which of these can be reduced when heated with carbon?
2. Match the items in List A with the responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided.Match the items in List A with the responses in List B by writing the letter of the correct
List A | List B |
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SECTION B (54 Marks)
Answer all questions in this section.
3.(a) Define the following terms:
(b) (i) List two advantages of liming.
View Ans(ii) State two roles of climate in the soil formation.
View Ans4. (a) Copper obtained from copper pyrites (CuFeS2) is impure for electrical wiring and has to be purified by electrolysis.
(i) Name the electrolyte and the electrodes used during electrolysis.
(ii) Write the observations that can be made during the electrolysis.
View Ans(b) The following flow diagram shows the stages in the contact process
(i) Give the names of element A, catalyst B and an acid C.
(ii) Write a balanced chemical equation for the formation of sulphur trioxide in stage 2
View Ans5. (a) Suggest one method of separating each of the following:
(i) Green solution from leaves.
(ii) Alcohol from water.
View Ans(b) Elements K, L, M and N have atomic numbers 6, 8, 9 and 20 respectively. Classify each element into its respective period and group.
View Ans6. (a) Give one example in each of the following:
(i) Alkali earth metals.
(ii) Noblegases .
(iii) Transition elements.
View Ans(b) Write the names of the following processes of changing matter from one state to another.
(i) Gas to liquid.
(ii) Ga s to solid.
(iii) Solid t o gas .
View Ans7 (a) Define the following:
( i ) Mole .
( i i ) Molarmass .
View Ans(b) 112 dm3 of oxygen gas was collected at s.t.p when a sample of lead nitrate was completely decomposed by heat. Calculate the volume of nitrogen dioxide gas produced.
View Ans8. (a) Distinguish manures from fertilizers. Give an example in each case.
View Ans(b) The following equation shows the reaction between hydrogen and iodine gas to form hydrogen iodide gas,H2(g) + I2(g) ? 2HI (g) ?H= -800Kj/mol. Giving a reason, explain what would happen to the position of equilibrium if
(i) temperature is lowered.
(ii) hydrogen iodide gas is pumped into the system.
View Ans9. (a) (i) Name the products formed when hydrogen sulphide react with chlorine gas. (ii) Mention two uses of hydrochloric acid.
View Ans(b) (i) Name the compound which causes temporary hardness of water and the compound which causes permanent hardness of water.
View Ans(ii) Write one balanced chemical equation in each case to show how to remove temporary and permanent hardness of water.
View Ans10. (a) (i) Define isomerism.
(ii) Draw and name two structural formulae of the isomers of C4H8.
View Ans(b) Carbon dioxide can be prepared by adding an acid to calcium carbonate.
(i) Using a named acid, write a balanced chemical equation for the reaction. (ii) Name all the products formed in (b) (i).
View Ans11 . ( a ) With the aid of a chemical equation, describe how you would prepare pure solid sodium chloride by the action of an acid and a base.
View Ans(b) (i) Why petroleum and coal are non-renewable sources of energy?
(ii) Give three alternatives to non-renewable sources of energy.
View AnsSECTION C (26 Marks)
Answer all questions in this section.
12. Three moles of nitrogen gas combine with five moles of hydrogen gas to form ammonium gas by Haber process.
13. In Tanzania, soil conservation is very important for Industrial Materials production. Explain six methods that are used to manage loss of plant nutrients from the soil.
View Ans