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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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CHEMISTRY EXAM FORM THREE

NAME ____________________________________________________________________  

TIME: 3HRS.

INSTRUCTIONS

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

ii) Attempt all questions in all sections

iii) Calculators, and cellular phones are NOT allowed

iv) The following Constants may be used.

Atomic Masses:

H = 1,    C = 12,     O = 16,    N = 14,   Na = 23

Mg = 24,   Al = 27,    S = 32,    Cl = 35.5,    Ca = 40,    Cu = 64,     Ag = 108

1 Faraday = 96500C

1 Litre = 1dm3 = 1000cm3

GMV at S.T.P = 22.4dm3

SECTION A (20 MARKS)

1. For each of the items, (i) – (x).  Choose the correct answer from the alternatives given and write a letter of your choice besides the item number.

1. Loose and Floppy clothing is not allowed is the Laboratory because:

1. Movement has to be fast
2. Will get wet when water splashes
3. It can catch fire or cause one to fall
4. It cause poor ventilation to the body

                                                                                                                                      ( )

2. The equation X2+(aq)  + 2e -         X, represents

1. Oxidation reaction
2. Reduction reaction
3. Displacement reaction
4. Neutralization reaction
5.                                                                                                                                  ( )

3. Which of the following statements about the hardness of water is not true?

1. Soft water readily forms lather with soap
2. Hard water does not reading form lather with soap
3. Permanent hardness of water is due to Sulphates of Calcium and Magnesium
4. Permanent hardness of water becomes soft in boiling.

                                                                                                                               ( )

4. Reaction between substance  A and B forms C, is referred to as;

1. Physical charge
2. Chemical change
3. Mixture
4. Dissociation

                                                                                                                                 ( )

5. 0.5g of hydrogen gas is exploded in air to produce water vapour the mass of water formed is;

1. 0.75g
2. 4.0g
3. 18g
4. 4.5g

                                                                                                                                 ( )

6. What volume of 0.2M H2SO4 will be required to neutralize 25cm5 0.5M KOH?

1. 3.125cm3
2. 6.125cm3
3. 6.315cm3
4. 31/25cm3

                                                                                                                                 ( )

7. An element P with atomic number 13 belongs to group – and period -----

1. II and 2
2. III and 3
3. III and 2
4. II and 3

                                                                                                                                 ( )

8. Precipitation reaction can be represented by the following equation

1. Ba2+ (aq)  +  SO42- (aq)   BaSO4(s)

2. H+ (aq)  + OH – (aq)   H2O(l)

3. Na+ (aq)   + Cl – (aq) Nacl (aq)

4. 2KCl O3 (s) MnO2 2Kcl )s)   + 3O2 (g)

                                                                                                                                 ( )

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