Chemistry 9701/35 Oct Nov 2013 | Cambridge AS Level Past Papers With Mark Scheme

1. Determination of the molecular identity of an organic acid by titration; molar mass calculation using sodium hydroxide, and distinguishing between methanoic, propanoic, and pent-2-enoic acid using a selective test.

2. Analysis of hydrated iron(II) sulfate; experimental calculation of water of crystallization (x), error identification in heating methodology, and suggestions for procedural improvements.

3. Identification of ions in a mixture using qualitative analysis techniques; heat and reaction-based observations to identify cations and anions, such as using NaOH, AgNO₃, and BaCl₂ tests.

4. Systematic identification of cations Al³⁺, Ca²⁺, Zn²⁺, and Pb²⁺ using precipitation, solubility, and reactivity differences with reagents like sodium hydroxide, ammonia, and potassium iodide.

5. Application of standard qualitative analysis notes for interpreting reactions of aqueous cations and anions, including visual indicators like precipitate color, solubility, and changes with excess reagents.

6. Observations and inferences from practical experiments, including test for gases and specific identification of carbonate, chloride, sulfate, and nitrate ions using reagents and qualitative notes.