Chemistry 9701/35 Oct Nov 2014 | Cambridge AS Level Past Papers With Mark Scheme

1. Determination of the degree of hydration (x) in sodium carbonate using titration with nitric acid and calculations involving molar mass and reaction stoichiometry.
2. Enthalpy changes for dehydration reactions of sodium carbonate using Hess's Law, including enthalpy calculations for reactions with hydrochloric acid.
3. Qualitative analysis of cations and anions through reactions with dilute acids, aqueous sodium hydroxide, ammonia, barium nitrate, and silver nitrate, emphasizing precipitate formation and gas evolution.
4. Error analysis in titration and calorimetric methods, including percentage error calculations and implications for experimental accuracy.
5. Use of Hess’s Law to calculate reaction enthalpy changes for dehydration and other multi-step processes, with focus on thermal effects and reaction pathways.
6. Identification of ions in unknown mixtures through systematic qualitative tests, including solubility patterns, precipitate observation, and gas evolution during heating.