THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL

CERTIFICATE OF SECONDARY EDUCATION EXAMINATION 

032/1  CHEMISTRY 1

 (For Both School and Private Candidates)

Time: 3 Hours  Thursday, 11^th October 2012 p.m.

 Instructions

1.  This paper consists of sections A, B and C.
2.  Answer all questions in this paper.
3.  Calculators and cellular phones 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, C = 12, O = 16, N = 14, Na = 23, Mg = 24, Al = 26, S = 32, Cl = 35.5, Ca = 40, Mn = 55, Fe = 56, Cu = 64.

 Avogadro’s 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 in the answer booklet provided.

(i)  Which one of the following sets of laboratory apparatus are used for measure volume?

1. Crucible, U-tube and volumetric flask
2. Test tubes, beakers and glass jar
3. Thistle funnel, separating funnel and beaker
4. Burette, pipette and measuring cylinder
5. Conical flask, test tube and measuring cylinder.

(ii)  The empirical formula of certain compound in CH₃. Its molar mass is 30 g. What will be its molecular formular?

1. CH₄
2. C₂H₄
3. C₂H₆
4. C₂H₈
5. C₄H₁₂

 (iii)  In order to produce the greatest amount of hydrogen in a short time, one gram of magnesium ribbon should react with

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

(iv)  Fractional distillation process of a mixture of water and ethanol is possible because

1. water and ethanol have the same boiling point
2. water has lower boiling point than ethanol
3. ethanol has lower boiling point than water
4. water and ethanol form partially immiscible liquid solution
5. water and ethanol are immiscible liquids.

 (v)  Which of the following substances represent a group of acidic oxides?

1. Carbon dioxide, carbon monoxide and sulphur dioxide
2. Sulphur trioxide, nitrogen dioxide and nnitrogen 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.
   

 (vi)  What will the molarity of a solution which contains 26.5 g of anhydrous sodium carbonate in 5 dm³ of solution?

1. 0.05 M
2. 0.25 M
3. 5.30 M
4. 0.025 M
5. 0.50 M

 (vii)  The Brownian movement is taken to be the evidence of the:

1. theory of association of water molecules
2. theory of ionization of electrolytes
3. theory of colloidal suspensions
4. kinetic theory of behavior of substances
5. Brownian theory.

 (viii)  One off the isotopes of an element X has an atomic number Z and a mass number A. What is the number of neutrons contained in the nucleus of the element X?

1. Z
2. A
3. A + Z
4. A – Z
5. Z – A

(ix)  C₂H₄Cl can be represented in different structures which are called

1. homologous series
2. isomers
3. structural formulae
4. identical structures
5. condensed structures.

(x)  _____ is the general term used to explain a mixture of different metals.

1. Alloy
2. Allotrope
3. Amphoteric
4. Amorphous 
5. Isotope.