(a)(i) Oxide of non-metals which dissolve in water to form acidic solution.
(ii) 1. Acidic oxides:- SO\(_2\)/CO\(_2\)/NO\(_2\), etc.
2. Basic oxides:- CaO/Na\(_2\)O/K\(_2\)O, etc.
3. Amphoteric oxides:- Al\(_2\)O\(_3\)/ZnO/PbO, etc.
4. Neutral oxides:- CO/N\(_2\)O, etc.
(b)(i) Heat of combustion is the heat change when one mole of a substance is completely burnt in oxygen or burnt in excess oxygen
(ii) Heat of neutralization is the heat change when one mole of water is produced as a result of a reaction between an acid and alkali in dilLte solution or the heat change when one mole of H+ from an acid reacts with one mole of OH\(^-\) from an alkali to form one mole of H\(_2\)O.
(ii)1. C\(_{(g)}\) + O\(_{2(g)}\) \(\to\) CO\(_{2(g)}\)
2. HaOH\(_{(aq)}\) + HCl\(_{(aq)}\) \(\to\) NaCI + H\(_2\)O\(_{(l)}\) \(\Delta\) Hn\(^o\)
3. Molar mass of C\(_4\)H\(_{10}\) = 12 x 4 + 1 x 10
= 48 + 10 = 58g mol\(^{-1}\) .
58g of C\(_4\)H\(_{10}\) = 5877kJ mol\(^{-1}\)
14.5 of C\(_4\)H\(_{10}\) = \(\frac{5877 \times 14}{58}\) kJ mol\(^{-1}\)
= + 1469.25 kJ.
(c)(i) Rhombic
Monoclinic
| Rhombic | Monoclinic |
| Yellow translucent crystal | Transparent amber crystal |
| Stable at temperature below 96°C | Unstable at temperature below 96°C |
| Higher density than monoclinic | Lower density than rhombic |
| Lower melting point | Higher melting point |
| Octahedral shaped | Needle shaped. |
(d)(i)(a) They are monoatomic gases
(b) They are chemically unreactive
(c) Have low melting/boiling point.
(ii) He — filling balloons. Ar — arc welding.
