Page 264 - Chemistry

ZnCO 3 (s) ZnO (s) + CO 2(g) √1 (penalize ½ if states are missing)

23. a) Iron III hydroxide
b) Concentrated sodium hydroxide is added at 4 atm pressure to the Bauxite at 160C
AL 20 3 dissolves in the sodium hydroxide leaving the iron III oxide as a solid

24. a) i) The oxygen produced at the anode reacts with hot carbon to form carbon (iv) oxide hence
corrodes it therefore needs replacement
ii) Graphite is inert and a poor conductor of heat hence helps to conserve heat

b) Aluminum has more number of valency electrons which are delocalized

Organic chemistry II (alkanoic acids and alkanols)
1. (i) Ethylbutanoate
(ii) CH 3CH 2CH 2 C – O – CH 2 – CH 3
(iii) Esters
O
2. a) –CH- CH- CH 2 – CH – CH 2- CH – CH 2 - CH
b) Polypheny/ ethane
3. Plastics may contain chlorine or fluorine compounds apart from hydrogen and carbon when
burnt, fluorine and chlorine compounds are released into the air destroying Ozone layer
4. (NH 4) 2 CO 3(s) 2NH 3(g) + CO 2(g) + H 2O (l)
5. The first amount of soap precipitates Ca 2+ (aq) and Mg 2+ (aq) ions and soften water.
Then additional soap dissolves oil from the fabric.
6. a) CH 3CH 2 O O CH 2CH 3 O

- NH – CH – C – NH – C – C – C –

H H
b) 0.00005mol. P = 0.515 g of monomer.
= 1.0 mole of poly mer = 1X 0.515 = 10300 g
0.0005
RFM ( C 4H 9ND 2)n = 48 + 9 + 32 = 103
= (C 4H 9NO 2) = 10300
103n = 10300
n = 100 molecules
7. Agent A – magnesium salt formed is soluble hence doesn‟t form scum
8. (a) Styrene/Phenylethene
H H

C = C

O H
(b)Addition polymerization
(c) – can be made into different shapes easily
- are cheaper
- are not corroded by acids, alkalis or air Any 1 correct
- are stronger and long lasting
- are water-proof
9. – Add water to the mixture and shake where ethanol dissolves in water while pentane is
immiscible.
*MAT
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