Chemistry 9701/35 Oct Nov 2019 | Cambridge AS Level Past Papers With Mark Scheme

1. Quantitative Analysis and Titration: Methods for determining the concentration of hydrochloric acid (HCl) by reacting it with magnesium powder and via titration with sodium hydroxide (NaOH). Includes calculations for moles of hydrogen gas, acid concentration, and modifications to improve accuracy.
2. Experimental Procedures: Use of water displacement, accurate measurement techniques, and titration with indicators to determine concentrations. Discussions on potential errors and improvements in experimental accuracy.
3. Gas Production and Stoichiometry: Determining the amount of gas produced and how it relates to the concentration of acid. Evaluation of excess reagent and its effects on calculations.
4. Chemical Reactions and Error Analysis: Identification of ions and effects of errors such as using less magnesium on acid concentration determination.
5. Qualitative Analysis: Identification of ions in unknown samples via color changes, precipitation reactions, and testing for gases like ammonia, chlorine, and carbon dioxide.
6. Ionic Reactions: Conducting tests for various cations and anions, with explanations for observed results and corresponding ionic equations for reactions.