Chemistry 9701/41 May June 2018 | Cambridge AS Level Past Papers With Mark Scheme

1. Sodium Oxide Reaction and Properties: Writing the reaction equation for sodium with oxygen, explaining why sodium oxide has a high melting point due to its ionic structure and lattice energy, and explaining the alkaline nature of the solution formed with water using the Brønsted-Lowry theory.
2. pH Calculation: Calculating the pH of a solution formed when sodium oxide reacts with water, and understanding the relation between sodium oxide's mole quantity and the solution’s pH.
3. Lattice Energy Calculation: Using given enthalpy data to calculate the lattice energy of sodium oxide, with proper interpretation of the values and concepts of lattice enthalpy in ionic compounds.
4. Sodium Sulfide vs. Sodium Oxide: Comparing the exothermic nature of sodium sulfide with sodium oxide, explaining why sodium sulfide is less exothermic based on the ionic bonds formed.
5. Reaction Rate and Catalysis: Defining the rate of reaction, identifying changes in the reaction mixture that affect reaction rate, and calculating the rate constant from experimental data.
6. Half-life and Rate Law: Determining the initial concentration of NO in an experiment and analyzing the order of reaction with respect to various reactants, drawing conclusions from half-life calculations about the reaction order.
7. Electrolysis and Redox Reactions: Understanding electrolysis reactions, identifying the products formed at electrodes, and explaining how oxidation and reduction occur in the electrolysis of molten calcium iodide.
8. Copper Complexes: Describing the formation of copper complexes with ligands, including their shapes, bond angles, and the reactions occurring when ammonia is added to copper solutions.
9. Environmental Chemistry: Understanding how NO acts as a catalyst in environmental reactions like the oxidation of sulfur dioxide, and explaining the resulting environmental consequences.
10. Aromatic Substitution: Investigating the electrophilic substitution reactions of cumene with chlorine, including the conditions for selective substitution in the aromatic ring or side-chain, and the products formed.