Page 186 - Chemistry

- Manufacture of ammonia.
- Conversion of coal to synthetic petrol.
(f) Zn (s) + H 2O(g) ZnO(s) + H 2(g) 1
(g) S,½ P,  ½ Q,  ½ R, ½
(h) It adds to unsaturated oils and hardens them. 1
10. a) i) Heating of copper (ii) Oxide to be shown on the diagram
ii) To drive out air because mixture of air and hydrogen is explosive when lit
iii) CuO (g) + H2 (g) __________ Cu (g) + H2O (g)
(penalize ½ mark for wrong S.S)
iv) To prevent re-oxidation of hot copper by the atmospheric oxygen
v) Reducing agent
vi) Black copper (ii) Oxide turns to brown showing that copper (ii) Oxide has
been reduced to copper
vii) Zinc is more reactive than hydrogen and therefore cannot be reduced by hydrogen

11. (a) Hydrogen gas

(b) - Calcium react with water forming calcium hydroxide solution
2
– Calcium hydroxide solution dissociates to produce calcium ion (Ca +ions) and hydroxide

-
(OH ) ions responsible for basic properties.

6. Structure of the atom and the periodic table

1. Na 2CO 3 + 2HNO 3 ____ 2NaNO 3 (L) + CO (q) + H 2O (C)
Mole ration 1 : 2
3
a) Moles of HNO 3 in 20cm = 20/1000 x 0.25
= 0.005 moles

3
b) Moles of Na 2CO 3 in 25cm = ½ of 0.005 moles
= 0.0025

3
c) If 25cm = 0.0025 moles
3
in 250cm = ?
250 x 0.0025
25
= 0.025 moles

RFM of Na 2CO 3 = 106
I mole of Na 2CO 3 = 106g
0.025 moles = ?
0.025 x 106
1
= 2.65g of Na 2CO 3
2. (a) A= 2.8.1

B= 2.1
(b) B

Strong attraction of the outermost energy level electron to the nucleus make it difficult
to remove This is due to smaller atomic radius compared to A
Or - Outermost electrons are closer to the nucleus hence higher force of attraction
3. R.A.M = (62.93 x 69.09) + (64.93 x 3091)
100
= 4347.834 + 2006.99
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