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 Year: 2020
Instructions
l. This paper consists of sections A, B and C with a total of fourteen (14) questions.
2.Answer all questions in sections A and B and one (1) question from section C.
3.Sections A and C carry fifteen (15) marks each and section B carries seventy (70) marks.
4.Cellular phones and any unauthorised materials are not allowed in the examination room.
5.Write your Examination Number on every page of your answer booklet(s).
6.The following constants may be used.
Atomic masses: H =l, C= 12, N=14, O= 16, Na = 23, S = 32, ca = 40, Cl = 35.5, cu = 64 Zn 65.
Avogadro's number 6.02 x 1023
GM V at s.t.p = 22.4 dm3 .
I Faraday = 96,500 coulombs.
Standard pressure = 760 mm Hg.
Standard temperature= 273 K.
I litre= I dm3 1000 cm3.
SECTION A (15 Marks)
Answer all questions in this section.
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) Which of the following pairs constitute the best methods for treating and purifying water?
(ii)A good fuel is the one which has
(iii) A rapid chemical reaction that releases energy in form of light and heat is called
(iv)Which one is the molecular formula for prop-I-yne?
(v)Which of the following is not a component of the First Aid Kit?
(vi)Which of the following is the correct sequence of the last two steps you should follow during the scientific procedure?
(vii)Consider the following reagents:
Which reagents are involved in the preparation of oxygen gas in the laboratory?
(viii)Why oxygen differs from other gases?
(ix)What is the best way of preparing hydrogen gas in the laboratory?
(x)What volume of hydrogen gas will be produced when 1.3 g of zinc granules react completely with excess dilute sulphuric acid at s.t.p?
2.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 |
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SECTION B (70 Marks)
Answer all questions in this section.
3.(a) Giving an example for each, give four uses of matter in daily life.
View Ans(b) Why are chemical symbols useful in Chemistry? Give three reasons. (7 marks)
View Ans4. (a) Give four laboratory apparatuses that are made up of porcelain/ceramic material.
View Ans(b) Outline three steps of administering First Aid to a person having a bruise on his leg resulting from a fist /hand blow. (7 marks)
View Ans5, (a) What is the molarity of a solution containing 10% by mass of calcium hydroxide in 0.5 dm3 of solution?
View Ans(b) 25 cm of a molar solution of sodium hydroxide is diluted to 85 cm . Calculate the concentration of the solution after dilution. (Give your answer in two decimal places). (7 marks)
View Ans6. (a)Briefly explain the basic steps you would follow in water treatment.
View Ans(b) Outline how to test for the purity of water. (7 marks)
View Ans7. (a) Briefly explain five importance of balancing chemical equations.
View Ans(b) Give a balanced chemical equation for the reaction between sodium carbonate and hydrochloric acid. (7 marks)
View Ans8.(a) Calculate the concentration in g /dm3 of vinegar (CH3COOH) if 25.0 cm3 of 0.1 M sodium hydroxide reacts with 12.5 cm of vinegar.
View Ans(b)By giving a reason, suggest the suitable indicator for the reaction in 8(a) above. (7 marks)
View Ans9.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 of the gas obtained was 4.12 dm3 and the gas relighted a glowing splint;
(a)name the gas that was produced.
View Ans(b)calculate the electric current that was flowing in the solution. (7 marks)
View Ans10.(a) Draw diagrams to show the atomic structures of the elements with atomic number l , 10, 16 and 19.
View Ans(b)Element X has 20 electrons and a mass number of 40. Work out the number of each type of nucleons present. (7 marks)
View Ansl l . 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.
View Ans(b)give the IUPAC name of the compound. (7 marks)
View Ans12.(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.
View Ans(b) 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. (7 marks)
View AnsSECTION C (15 Marks)
Answer one (1) question in this section.
13.Carbon is one of the elements that have allotropes. Explain how the allotropes of carbon differ from each other. (15 marks)
View Ans14. Despite its corrosiveness, sulphuric acid is very important in industry. Explain the importance of sulphuric acid in industries by giving six points. (15 marks)
View Ans