Chemistry 9701/52 Oct Nov 2014 | Cambridge AS Level Past Papers With Mark Scheme

1. Experimental determination of the composition of a zinc-aluminium-copper solder alloy; sequential extraction of copper, aluminium hydroxide, and zinc hydroxide using sulfuric acid and ammonia.

2. Titration-based determination of the acid dissociation constant (Ka) for a monoprotic weak acid (HA); plotting titration curve, pH determination at half-equivalence, and calculation of equilibrium concentrations.

3. Calculations involving stoichiometry of neutralization reactions; derivation of molar concentrations, masses of components, and relative molecular mass (Mr) from experimental data.

4. Identification of anomalies in titration data; potential errors due to pH measurement inaccuracies or systematic deviations.

5. Selection of appropriate pH indicators based on observed titration range and determination of end-point precision.

6. Experimental limitations in accuracy for determining molecular mass and concentration; effects of reagent purity, measurement errors, and solution stability.