Chemistry 9701/53 May June 2016 | Cambridge AS Level Past Papers With Mark Scheme

1. Measuring Hydrogen Gas Produced from Lithium Reaction:
- Experimental Setup: The paper asks how to measure the volume of hydrogen gas produced by reacting lithium with water and includes a diagram of apparatus setup.
- Procedure and Safety: It covers the necessary steps to prepare the lithium, the safety precautions to take, and the calculations involved in determining the amount of hydrogen gas produced and the corresponding volume of gas collecting apparatus required.
- Titration Method: This includes titration of lithium hydroxide to determine the relative atomic mass of lithium, requiring an understanding of accurate measurement and neutralization techniques.

2. Activation Energy Determination:
- Magnesium and Hydrochloric Acid: The experiment involves determining the activation energy (Ea) for the reaction between magnesium and hydrogen ions from hydrochloric acid by measuring the time for magnesium to disappear and using the mathematical relationship to calculate Ea.
- Experimental Procedure: The procedure outlines the use of different temperatures to study the reaction rate, and the collection of data for plotting a graph of log10(1/t) vs. 1/T.
- Data Analysis: Questions focus on processing the experimental data, identifying anomalies, and calculating the gradient of the graph to determine the activation energy.
- Additional Considerations: The paper asks for evaluation of reliability, and the effect of stirring, temperature, and acid concentration on the reaction.

3. Practical Chemistry:
- Observing Reactions: The experiment emphasizes recording observations during the reaction, calculating rates, determining anomalies in experimental data, and assessing the accuracy and reliability of results.