CHEMISTRY SCHEME OF EXAMINATION

There will be three papers, Papers 1, 2 and 3 all of which must be taken. Papers 1 and 2 will be a composite paper to be taken at one sitting. PAPER 1: Will consist of fifty multiple choice objective questions drawn from Section A of the syllabus. Candidates will be required to answer all the questions within 1 hour for 50 marks.

PAPER 2: Will be a 2-hour essay paper covering the entire syllabus and carrying a maximum of 100 marks. The paper will be in two sections: Sections A and B.

Section A: Will consist of ten short structured questions drawn from the common portion of the syllabus ( ie Section A of the syllabus). Candidates will be required to answer all the questions for 25 marks.

Section B: Will consist of two questions from the common portion of the syllabus ( ie Section A of the syllabus) and two other questions from the section of the syllabus which is perculiar to the country of the candidate (ie either Section B or C of the syllabus).

Candidates will be required to answer any three of the questions. Each question shall carry 25 marks.

PAPER 3: This shall be a 2-hour practical test for school candidates or1 hour 30 minutes alternative to practical work test for private candidates. Each version of the paper shall contain three compulsory questions and carry 50 marks. The questions shall be on the following aspects of the syllabus:

one question on quantitative analysis; one question on qualitative analysis;

the third question shall test candidates’ familiarity with the practical activities suggested in the syllabus.

 

PAPER 1(OBJECTIVE TEST)

1. Isotopes of the same element have the same number of A. protons, neutrons and electrons. B. protons and neutrons but different number of electrons. C. protons and electrons but different number of neutrons. D. neutrons and electrons but different number of protons.

2. Which type of chemical bond is formed by the transfer of electrons? A. Covalent B. Dative C. Ionic D. Metallic 3. The concentration of an aqueous solution is 5mg dm-

3. Determine is the concentration in parts per million (ppm). A. 500 ppm B. 50 ppm C. 10 ppm D. 5 ppm

4. Consider the following species: H, H+, H-. What is the number of electrons in each of the species respectively? A. 1, 0, 2B. 0, 1, 2C. 2, 1, 0D. 1, 2, 0

5. Two electrons can occupy the same orbital if they have different A. angular momentum quantum numbers. B. magnetic quantum numbers. C. principal quantum numbers. D. spin quantum numbers.

6. What mass of NaOH is required to make 250 cm3 of 0.10 mol dm-3 solution? [Na = 23, O = 16, H = 1] A. 1 gB. 4 gC. 8 gD. 16 g

 

PAPER 3 (PRACTICAL)

1.A is a solution of HCl of unknown concentration. B contains 1.00g of NaOH in 250cm3 of solution. (a)Put A into the burette and titrate it against 20.0cm3or 25.0cm3 portions of B using methyl orange as indicator.

Tabulate your burette readings and calculate the average volume of A used. The equation for the reaction involved in the titration is NaOH + HCl

 NaCl + H2O (b)From your results and the information provided above, calculate the (i) concentration of Ain moldm-3; (ii) concentration of A in gdm-3. [H=1.0;O=16; Na=23;Cl=35.5]

2.C is a solution of a simple salt. Carry out the following exercises on C. Record your observations and identify any gases evolved. State the conclusions you draw from the result of each test. Put about 2cm3each of C in three separate test tubes.

(a)To the first portion of C add NaOH(aq)in drops and then in excess.

(b)To the second portion of C add a few drops of AgNO3(aq) followed by excess HNO3(aq).

(c) To the third portion of C add about 2cm3of KI(aq).

3. State the apparatus that could be used to (i)separate liquids whose boiling points are within a range of five degrees; (ii) change vapour into liquid during distillation; (iii) separate a mixture of starch and water.