Chemistry 9701/36 Oct Nov 2020 | Cambridge AS Level Past Papers With Mark Scheme

1. Quantitative analysis of hydrated potassium carbonate: Determining the formula by reacting with hydrochloric acid and collecting CO2 gas, including calculations for moles of CO2, relative formula mass, and determining the value of \\(x\\) in K₂CO₃•\\(x\\)H₂O.
2. Suggestions for improving experimental accuracy by addressing the solubility of CO₂ in water and modifying the procedure.
3. Enthalpy change calculations: Measuring temperature changes during the reaction of sodium carbonate with hydrochloric acid to determine enthalpy changes and how hydration of sodium carbonate affects the reaction.
4. Analysis of experimental changes with different concentrations of HCl, including predicting how temperature changes would vary.
5. Qualitative analysis: Testing solutions for cations and anions through reactions with reagents like ammonia, sulfuric acid, and potassium manganate, followed by identifying the ions present in given samples.
6. Tests for anions: Performing tests on salts to identify anions using reagents, and observing changes like precipitate formation and reactions with acids.
7. Enzyme catalysis: Describing how enzymes like fumarase catalyze reactions and explaining their mechanism using labeled diagrams.
8. Organic chemistry: Understanding the reactions of proline and its derivatives, including their synthesis, and studying the secondary structure and peptide bond formation.
9. Synthesis of proline: Following a multi-step synthesis process and understanding the reaction mechanisms, with a focus on functional groups and reagents used.
10. Buffer solutions: Calculating the pH of buffer solutions and predicting the behavior of amino acids at different pH levels using electrophoresis.