Chemistry 9701/12 May June 2019 | Cambridge AS Level Past Papers With Mark Scheme

1. Boltzmann Distribution and Catalysis: Effect of adding a catalyst (manganese(IV) oxide) on the Boltzmann distribution curve of molecular energies in aqueous hydrogen peroxide.
2. Mass Spectrometry and Isotopes: Expected peaks in mass spectrometry for oxygen isotopes (O\\(_2\\)) and interpretation of molecular mass spectra.
3. Ionization Energies and Ionic Compounds: Identifying ionic compounds formed based on successive ionization energies and periodic trends in elements like sodium, magnesium, and calcium.
4. Bonding and Orbital Overlap: Identifying orbital overlap in the formation of a sigma bond in ethene (C\\(_2\\)H\\(_4\\)).
5. Physical Properties of Substances: Analyzing the properties of substances like potassium iodide based on melting points and electrical conductivity.
6. Gas Reactions and Ideal Gas Law: Application of ideal gas laws to calculate pressure in a reaction vessel with gases X, Y, and Z at a given temperature.
7. Molecular Structures: Identifying simple molecular substances from a list of materials such as C\\(_60\\), iodine, graphite, and graphene.
8. Reaction Pathway and Energy Diagrams: Interpreting energy diagrams to assess the activation energy and enthalpy changes in chemical reactions.
9. Chlorine Reactions: Identifying the possible reactants (like Cl\\(_2\\)O, Cl\\(_2\\)) involved in the formation of HCl and HClO\\(_3\\) in reaction with water.
10. Equilibrium and Reaction Concentration: Determining the concentration of ethyl ethanoate in an equilibrium system involving ethanoic acid and ethanol.
11. Catalysis and Reaction Rates: Identifying examples of heterogeneous catalysis, including sulfuric acid in esterification and the Contact process.
12. Periodic Trends and Element Properties: Understanding atomic radius, oxidation states, and acidity trends across periods and groups in the periodic table.
13. Reaction Products and Precipitation: Analyzing the effect of different solutions like NH\\(_3\\) and Ba(NO\\(_3\\))\\(_2\\) on the precipitation of ions in magnesium sulfate solutions.
14. Chemical Decomposition and Compound Identification: Predicting the products of reactions like the thermal decomposition of magnesium nitrate or the reaction of acids with chloride salts.
15. Thermodynamics and Acid-Base Chemistry: Calculating pH changes, determining acid dissociation constants (Ka), and comparing the effects of different acids on pH.
16. Organic Synthesis and Reactions: Identifying reaction types in organic chemistry, such as the elimination reactions of bromoethane and the dehydration of alcohols.
17. Polymer Chemistry: Identifying the monomers that form a given polymer and understanding biodegradation trends in polymers like nylon-6.
18. Isomerism in Organic Compounds: Identifying isomers of organic compounds such as but-2-ene and understanding cis-trans isomerism.
19. Reaction Mechanisms in Organic Chemistry: Analyzing the mechanism of esterification and the reactions of different organic compounds with reagents like LiAlH\\(_4\\).
20. Mass Spectrometry Analysis and Structural Elucidation: Using mass spectrometry and NMR data to determine the structure and fragmentation patterns of organic molecules.