Chemistry 9701/33 Oct Nov 2010 | Cambridge AS Level Past Papers With Mark Scheme

1. Titration of Hydrochloric Acid: The experiment involves determining the concentration of hydrochloric acid by titrating it with sodium thiosulfate, using potassium iodate and potassium iodide to release iodine in the presence of excess acid. The volume of thiosulfate required is noted for consistency and calculation.
2. Titration Data and Calculations: The results of the titrations are used to calculate the moles of iodine reacted, the moles of sodium thiosulfate used, and ultimately the concentration of HCl in the sample.
3. Error Analysis and Precision: The method calculates potential errors associated with burette readings and pipetting. The maximum errors in measurements are determined and expressed as a percentage of the total volume used.
4. Decomposition of Copper Carbonate: The heating of copper carbonate (CuCO₃.Cu(OH)₂.H₂O) to produce copper(II) oxide (CuO) is studied by measuring mass loss, with the theoretical and observed mass loss percentages analyzed.
5. Partition Coefficient of Succinic Acid: The experiment determines the partition coefficient (K) of succinic acid between water and diethyl ether, involving titrations with sodium hydroxide to measure concentrations and graphically analyze the data.
6. Qualitative Analysis of Metal Ions: Various solutions containing metal ions (Al³⁺, Mg²⁺, Pb²⁺, Zn²⁺) are tested with sodium hydroxide, ammonia, and potassium iodide to identify the metal cations present, using precipitation and color change observations.