Chemistry 9701/43 Oct Nov 2016 | Cambridge AS Level Past Papers With Mark Scheme

1. Copper Chemistry:
- Electronic configurations of copper atoms and ions, and the properties of copper complexes, such as the reaction between [Cu(H₂O)₆]²⁺ and Cl⁻ ions.
- The shapes of copper complex ions and the concept of stability constants.
- Understanding bidentate ligands, such as ethane-1,2-diamine, and the significance of their stability constants.

2. Nickel and Stereoisomerism:
- The stereoisomerism of [Ni(en)₃]²⁺ (where "en" is ethane-1,2-diamine), including drawing three-dimensional diagrams of its stereoisomers.

3. Brønsted-Lowry Acidity:
- The basic nature of ethane-1,2-diamine and its reaction with hydrochloric acid.
- Explanation of the behavior of ethane-1,2-diamine as a Brønsted-Lowry base.

4. Polymerization:
- Reactions involving ethane-1,2-diamine and ethanedioic acid, leading to the formation of biodegradable polymers.

5. Copper Carbonates and Thermal Decomposition:
- The thermal decomposition of copper(II) carbonate and Group 2 carbonates, with explanations of thermal stability trends.

6. Gibbs Free Energy and Spontaneity:
- Calculating Gibbs free energy changes (ΔG°) for reactions, using standard entropy (S°) and enthalpy (ΔH°) values.
- Understanding the effect of temperature on spontaneity and calculating the minimum temperature required for a reaction to be spontaneous.

7. Electrochemistry:
- Calculating electrode potentials, including the effect of concentration changes on electrochemical cell potentials.
- Understanding the principles of electrochemical cells and the Nernst equation.

8. Chemical Reactions and Titration:
- Using titration data to determine the concentration of chlorate(I) ions in bleach.
- Identifying suitable indicators for titrations and interpreting the expected color changes at the endpoint.

9. Buffer Systems:
- Explanation of the buffering action of carbonic acid and bicarbonate ions in blood to maintain pH.
- Calculating the pH of a solution using the Henderson-Hasselbalch equation.