chemistry form 2

THE UNITED REPUBLIC OF TANZANIA

CERTIFACATE OF SECONDARY EDUCATION EXAMINATION

CHEMISTRY

NAME ____________________________________________________________________  

TIME: 2:30 HRS.

INSTRUCTIONS

i)This paper consists of sections A, B and C

ii) Answer all questions in both sections

iii) All written must be in Blue or Black pens except in drawing which should in pencil.

1. Questions (i  -   x) are multiple choice items. Write down the letter of the most correct answer.

1. How many protons, Neutrons and electrons are there in an atom represented by the symbol 35

             17B  ?

Protons Neutrons Electrons

1.             35     17        18
2.             17     18        17
3.             17     35        18
4.             18    17        35

2. Which of the following chemical species have the same number of electrons?

1. K+,   Ca2+,    Cl-   and  Ar
2. Cl,     Be,   and O2-
3. O2,   Ca2+,   and Mg2+
4. Na+,   Mg2+ ,   Be 2+  and Li

3. Which of the following sets of apparatus are suitable for measuring volume of solutions.

1. Burette, pipette, and beaker
2. Burette, pipette, and conical flask
3. Measuring cylinder, burette and pipette;
4. Burette, flat bottomed flask and pipette

4. One isotope of an element has atomic number A and mass number M. how many neutrons are there in the nucleus of its atom?

1. M (b) A (c ) A – M (d) M – A

5. The total number of protons and neutrons in the nucleus of an atom is called

1. Valency number (c) Molecule number
2. Atomic number (d) Mass number.

6. Hydrogen gas can be collected by downward delivery because

1. It burns in air with pop-sound
2. It is more soluble than air
3. It is Lighter than air
4. It can fill balloons

7. Oxidation may be defined as

1. Loss of hydrogen by a substance
2. Grain of hydrogen by a substances
3. Reactions in which oxygen it lost
4. Reactions in which electrons are increased

8. Which of the following sets of symbols represents isotopes

1. 167W           168W       169 W

2. 168X   178 X           188 X

3. 168 X 178 X    189 X

4. 167 Y 178 Y    189  Y

9. The Valency of an element with atomic number 10 is

1. 2 (b) 3 (c) 0 (d) 1

10. Which of these electronic configurations are of metals?

1. 2:8:8:1  and  2:8:8:7
2. 2:8:3 and 2:8
3. 2:8:8:1 and 2:8:3
4. 2:8:6 and 2:8:8:7

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