(a) Arrange the three states of matter in order of decreasing: (i) kinetic energy; (ii) force of cohesion. (b) Consider the redox reaction equation: (i) Sta...

(a)

(i) Decreasing kinetic energy: gas > liquid > solid.

(ii) Decreasing force of cohesion: solid > liquid > gas.

(b) For the reaction \( \text{Mg} + 2\text{HCl} \to \text{MgCl}_2 + \text{H}_2 \):

• (i) I. Magnesium: oxidation number changes from 0 to +2. II. Hydrogen: from +1 to 0.
• (ii) I. Oxidized: magnesium (Mg). II. Reduced: hydrogen (H⁺).
• (iii) Oxidizing agent: hydrochloric acid (HCl / H⁺).

(c)(i) Two differences between boiling and evaporation:

1. Boiling occurs at a fixed temperature (the boiling point) and throughout the whole liquid with bubbles forming, whereas evaporation occurs at any temperature and only at the surface of the liquid.
2. Boiling requires an external supply of heat and produces no cooling, whereas evaporation uses the internal energy of the liquid and produces cooling.

(c)(ii) Reducing the atmospheric pressure lowers the boiling point of water, so it boils at a temperature below 100 °C.

(d) The equilibrium constant K indicates the extent to which a reaction proceeds and where the position of equilibrium lies: a large K means the products are favoured (reaction nearly complete), while a small K means the reactants are favoured.

(e) C₃H₇COOH is butanoic acid; (CH₃)₃COH is 2-methylpropan-2-ol.

(f) Because a functional group is the atom or group of atoms responsible for the characteristic chemical reactions of a compound. Compounds sharing the same functional group have similar chemical properties, so classifying by functional group makes their study systematic and their reactions predictable.

(g) Three differences between solubility of solids and of gases in liquids:

1. The solubility of most solids increases with a rise in temperature, whereas the solubility of gases decreases with a rise in temperature.
2. The solubility of gases increases markedly with pressure, whereas that of solids is virtually unaffected by pressure.
3. Dissolving a solid is generally accompanied by absorption of heat (endothermic), whereas dissolving a gas is generally accompanied by release of heat (exothermic).

(h) \[ 2\text{F}_2 + 2\text{H}_2\text{O} \to 4\text{HF} + \text{O}_2 \]

(i) The basicity of an acid is the number of replaceable (ionizable) hydrogen ions produced by one molecule of the acid in aqueous solution.