Chemistry 9701/33 Oct Nov 2016 | Cambridge AS Level Past Papers With Mark Scheme

1. Titration of Hydrogen Peroxide:
- Performing a titration to determine the concentration of hydrogen peroxide (H₂O₂) by reacting it with acidified potassium manganate(VII) (KMnO₄).
- Calculating the moles of KMnO₄ and H₂O₂ from the titration data and determining the concentration of hydrogen peroxide in the original solution.

2. Reaction Rate Measurement:
- Measuring the rate of reaction between hydrogen peroxide and iodide ions (I⁻), using sodium thiosulfate (Na₂S₂O₃) and starch as indicators.
- Using the rate of the reaction to calculate the concentration of thiosulfate ions in the solution.

3. Qualitative Analysis:
- Identifying metal cations (such as Al³⁺, Cu²⁺, Fe²⁺, Fe³⁺, Zn²⁺) and anions (such as CO₃²⁻, SO₄²⁻, Cl⁻, NO₃⁻) by conducting tests with appropriate reagents and recording observations.
- Testing for gases like ammonia (NH₃), carbon dioxide (CO₂), chlorine (Cl₂), hydrogen (H₂), and oxygen (O₂), and understanding their identification through relevant reactions and tests.

4. Experimental Techniques:
- Handling of solutions, pipetting, titrations, and measurements of reaction time to determine reaction rates.
- Performing experiments to observe color changes, precipitate formation, and solubility in excess reagents.