Chemistry 9701/33 Oct Nov 2017 | Cambridge AS Level Past Papers With Mark Scheme

1. Reaction and Titration of Copper(II) Sulfate: Determining the value of x in hydrated copper(II) sulfate, CuSO4.xH2O, by reacting Cu2+ ions with iodide ions, producing iodine, and titrating the iodine with thiosulfate.
2. Calculations of Moles and Concentrations: Calculating moles of thiosulfate, Cu2+ ions, and the concentration of Cu2+ in the solution, and determining the value of x in CuSO4.xH2O from these values.
3. Experimental Accuracy and Modifications: Analyzing the maximum percentage error in titration and suggesting methods for improving the accuracy of the experiment by modifying reagent measurements.
4. Heating and Mass Loss of Hydrated Barium Chloride: Determining the value of y in BaCl2.yH2O by heating the compound and measuring the mass loss, calculating the moles of BaCl2 and water lost.
5. Thermal Stability and Decomposition of Barium Chloride: Explaining how incomplete heating affects the value of y, and proposing methods to improve the accuracy of mass loss measurements in the barium chloride experiment.
6. Qualitative Analysis of Salts: Identifying ions in solutions of FA 6 and FA 7 using various tests and observations, including reactions with barium chloride and silver nitrate.