Chemistry 9701/53 Oct Nov 2019 | Cambridge AS Level Past Papers With Mark Scheme

1. Synthesizing Yttrium Barium Copper Oxide (YBa2Cu3O7): Calculating the minimum masses of BaCO3 and CuO required to react with Y2O3 to achieve a molar ratio of 1:2:3, and ensuring the highest yield of YBa2Cu3O7 is obtained after the heating process.
2. Titration for Cu3+ Ion Proportion: Explaining the procedure for determining the proportion of Cu3+ ions in YBa2Cu3O7, including steps involving reduction reactions and subsequent titration to determine the amount of Cu3+ present.
3. Electrochemical Analysis for Cu3+ Ions: Using electrochemical data to understand the necessity of removing Cu2+ ions by forming insoluble complexes, and explaining the required neutralization steps in the titration procedure.
4. Preparation of Sodium Citrate Solution: Calculating the mass of sodium citrate required for a 1.0 mol/dm³ solution and describing how to prepare it accurately.
5. Titration Data Analysis: Identifying issues with titration methods and suggesting improvements to the technique, ensuring accurate measurements and calculations.
6. Polymer Solution Viscosity Experiment: Understanding the capillary viscometer setup and the significance of rinsing the equipment with specific solvents.
7. Graphing and Calculation for Polymer Viscosity: Plotting data and calculating the relationship between concentration and viscosity, then determining the molecular mass of poly(phenylethene) based on the results.
8. Effect of Temperature on Solution Viscosity: Predicting how temperature influences viscosity and providing methods to ensure accurate temperature control during the experiment.
9. Polymer Molecular Mass Calculation: Using experimental data to determine the mean molecular mass (Mr) of poly(phenylethene) and calculating the number of repeat units in the polymer (x).
10. Intermolecular Forces in Solvent-Solute Systems: Explaining how the intermolecular forces between solvent and solute affect the polymer's properties, particularly for poly(ethenol) and poly(phenylethene) dissolved in different solvents..