Page 204 - Chemistry

(iv) U – Ammonia chloride 1
V – Sodium hydrogen carbonate. 1

(b) (i) HN 3(g) + H 2O(l) + CO 2(g) + NaCl(aq) NH 4Cl(aq) + NaHCO 3(s)
OR
NH 3(g) + H 2O(l) + CO 2(g) NH 4HCO 3(aq)
NH 4HCO 3(aq) + NaCl(aq) NH 4Cl(aq) + NaHCO 3(s)

(ii) NaHCO 3 Na 2CO 3(s) + CO 2(g) + H 2O (l)

(iii) Ca(OH) 2(s) + 2NH 4Cl(aq) CaCl 2 + 2NH 3(g) + 2H 2O(l)

c) - Manufacture of glass.
- Softening of hard water.
- Manufacture of papers.
- Manufacture of soap.
- Refining of metals.

17. (a) (i) – The gas is collected over water
- The gas is not passed through a drying agent
(ii) PbCl 2 is formed which is insoluble hence prevents contact between the carbonate
and the acid Heat
(iii) CO 2(g) + C(s) 2CO(g)
CO 2(g) + 2NaOH (aq) Na 2CO 3(aq) + H 2O (l)

(iv) – Solid CO 2 used as a refrigerant
 Used in making aerated drinks
 Solid CO 2 is used in cloud-seeding
 CO 2 used as an ingredient/air material in solvary process
(v) – Denser than air
- Does not support combustion (burning)
(b) Reducing Property
+
(c)- Al 2(CO 3) 3 hydrolyses in water/moisture forming H ions which reacts with the carbonate
and dissolves
Heat
(d) (NH 4) 2 CO 3(s) NH 3(g) + CO 2(g) + H 2O (g)

18. Brown fumes of a gas are produced as the charcoal dissolves in the acid. The charcoal
reduces nitric (V) acid to nitrogen (IV) oxide gas that is brown while the charcoal is oxidized
to carbon (IV) oxide.

19. (a) Due to formation of calcium hydrogen carbonate which is a soluble salt

(b) 2CaCO 3(s) + 2CO 2(g) + 2H 2O 23Ca(HCO 3) 2(aq)
(- Award 1mk if equation is correctly balanced
- Penalize ½ mk if equation if not balanced)
20. a) A – Concentrated sulphuric acid (vi) acid √1
b)
c) HCOONa (s) + H 2SO 4 HCOOH (L) + NaHSO 4(S)

Hence; HCOOH (l) CO (g) + H 2O (L)

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