Chemistry 9701/33 May June 2011 | Cambridge AS Level Past Papers With Mark Scheme

1. Iron(II) Salt Titration: Calculating the percentage of iron in an unknown iron(II) salt using titration with potassium manganate(VII), applying stoichiometric calculations to determine the moles of Fe²⁺.
2. Magnesium Sulfate Purity: Determining the percentage of magnesium sulfate heptahydrate in an impure sample by heating to remove water and calculating mass changes.
3. Qualitative Analysis of Ions: Identifying ions in unknown solutions through precipitation, solubility tests, and reactions with reagents like sodium hydroxide, ammonia, and barium chloride.
4. Experimental Error Analysis: Assessing errors in weighing and measuring, calculating percentage errors, and improving experimental accuracy in determining the purity of compounds.
5. Inorganic Reaction Chemistry: Understanding oxidation states in reactions like the reduction of lead(IV) chloride, and analyzing changes in oxidation numbers of species like bromine and iodine in various reactions.