Chemistry 9701/53 Oct Nov 2016 | Cambridge AS Level Past Papers With Mark Scheme

1. Titration of Barium Chloride:
- Determining the concentration of chloride ions in barium chloride solutions using silver nitrate titration with potassium chromate as an indicator.
- Identifying potential interferences and how to prevent them using sulfuric acid to protect against interference from Ba²⁺ ions.

2. Titration Experiment Planning:
- Planning a titration experiment to determine the formula of hydrated barium chloride (BaCl₂.xH₂O) using appropriate volumetric apparatus.
- Describing the procedure for preparing the barium chloride solution, titration setup, and steps to ensure the reliability of results.

3. Calculations:
- Determining the value of x in hydrated barium chloride (BaCl₂.xH₂O) from experimental data, including the concentration of Ba²⁺ ions in solution and the molar mass of the hydrated compound.

4. Hazards and Safety Precautions:
- Identifying hazards related to chemicals used in the experiment (e.g., barium chloride, potassium chromate), and suggesting safety precautions, excluding eye protection.

5. Optical Rotation and Reaction Kinetics:
- Using optical rotation data to analyze the rate of hydrolysis of sucrose, applying first-order kinetics to determine rate constants and half-life.
- Plotting the data and evaluating the results to confirm the relationship between concentration and reaction rate.

6. Reaction Order and Rate Constants:
- Using the data from two experiments with different temperatures to calculate rate constants, explain anomalies, and deduce whether the second reaction was faster due to higher temperature.