Chemistry 9701/22 May June 2015 | Cambridge AS Level Past Papers With Mark Scheme

1. Characteristics of subatomic particles (proton, neutron, electron), calculation of isotopic mass using magnesium isotopes, and empirical formula determination for a compound containing Mg, O, H, and Cl.
2. Electrolysis of molten MgCl₂ for magnesium production; electrode reactions and the impact of HCl on magnesium oxide impurities.
3. Acid-base behavior of Period 3 oxides, their reactions with NaOH or HCl, and structural effects on their chemical properties.
4. Contact process for H₂SO₄ production: oxidation of galena, equilibrium considerations for SO₃ formation using Le Chatelier's principle, and safety issues in SO₃ hydration.
5. Quantification of SO₂ in wine through titration with iodine using starch indicator; calculations for SO₂ concentration and mass in wine samples.
6. Reaction mechanism for ethane chlorination, bond energy calculations for enthalpy change, and production of by-products like butane.
7. Identification of isomers of C₅H₁₀O, including aldehydes and carbonyl compounds, based on branching, chirality, and structural features.
8. Distinction between isomers using chemical tests such as Tollen's reagent and Fehling's solution, applicable to aldehydes and ketones.