Chemistry 9701/42 May June 2019 | Cambridge AS Level Past Papers With Mark Scheme

1. Copper(I) and Copper(II) Chemistry: Understanding the electronic configuration and colors of copper(II) ions in different complex forms.
2. Solubility Product and Complex Formation: Calculating the solubility of silver bromide (AgBr) and understanding why AgBr dissolves in concentrated ammonia due to complex formation with \\( [Ag(NH3)2]^+ \\).
3. Electrochemical Measurements: Measuring the standard electrode potential for silver and constructing equilibrium expressions for reactions involving silver and ammonia.
4. Group 2 Carbonates: Writing decomposition equations for Group 2 carbonates, explaining their thermal stability, and predicting the stability of various carbonates like calcium carbonate.
5. Transition Elements: Understanding bonding between ligands and transition elements, writing formulas for coordination complexes, and explaining stereoisomerism in transition metal complexes.
6. Reaction Kinetics: Analyzing the rate law for the reaction between propanone and iodine, calculating rate constants, and understanding the effect of temperature on reaction rates.
7. Acid-Base Chemistry: Understanding the behavior of amino acids in various solutions, drawing zwitterions, and explaining the properties of different amino acids and their reactions.
8. NMR Spectroscopy: Predicting the number of peaks in NMR spectra for compounds, understanding why some peaks disappear in D2O, and drawing the structures of organic compounds based on NMR data.
9. Organic Synthesis: Determining the products of reactions involving different reagents, identifying reaction types, and suggesting synthetic routes for organic molecules.
10. Polymer Chemistry: Understanding the formation and characteristics of polyamides like nylon-6, their biodegradability compared to polyalkenes, and the mechanism of polymer formation.