Chemistry 9701/52 Oct Nov 2018 | Cambridge AS Level Past Papers With Mark Scheme

Here is a summary of the tasks based on the uploaded document:

1. Separation of Metal Ions from Waste Water: The process involves forming precipitates using reagents like HCl, (NH₄)₂CO₃, and (NH₄)₂S. You are asked to plan a flowchart with specific reagents and identify substances removed during filtration.

2. Neutralization and Precipitation: Discusses the need for neutralizing the sample between steps 1 and 2 of the process to enable proper reaction conditions.

3. Measuring Concentration of Metal Ions: Includes methods for determining the concentration of X²⁺ ions in the sample by heating a precipitate and measuring mass loss, followed by addressing the problems with this method and how they affect the results.

4. Preparation of Urea Solutions: Explains the steps to prepare a more concentrated urea solution and then dilute it for use in experiments. The document also outlines a procedure for preparing a 5.00 × 10⁻³ mol/dm³ solution of urea, using volumetric flasks and other equipment.

5. Conductivity Measurement in Urea Hydrolysis: The student measures the conductivity of a urea solution as hydrolysis occurs, and you are asked to plot graphs, calculate the rate of hydrolysis, and explain why conductivity changes during the reaction.

6. Effect of Silver Nitrate on Urease Activity: Sketching a graph of conductivity changes when silver nitrate is added to inhibit urease activity. Additionally, you are to explain the precautions needed when handling chemicals like silver nitrate and urease.

7. Chemical Hazards: Understanding the hazards associated with silver nitrate, urea, and urease, including recommendations for safety precautions to minimize risks.

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