Chemistry 9701/51 May June 2020 | Cambridge AS Level Past Papers With Mark Scheme

1. Investigation of dipole-dipole interactions between trichloromethane and propanone through temperature change measurements, including calorimetry techniques and enthalpy calculations.

2. Thermal decomposition of lead nitrate to produce nitrogen dioxide and oxygen; separation of gases based on boiling and melting points and analysis of experimental apparatus for optimal condensation.

3. Equilibrium study of nitrogen oxides (NO₂/N₂O₄): calculation of equilibrium constant \\( K_p \\) across temperatures, graphical analysis of \\( \\log K_p \\) vs. \\( \\frac{1}{T} \\), and determination of enthalpy change (\\( \\Delta H \\)) from gradient calculations.

4. Analysis of experimental data for precision and accuracy, including methods for improving data reliability and reducing systematic and random errors in kinetic studies.

5. Influence of temperature on equilibrium constants and reaction mixture color changes based on Le Chatelier’s principle, reflecting exothermic or endothermic nature of reactions.

6. Practical implications of apparatus configuration, insulation, and sample handling to enhance accuracy and minimize heat loss or volatility in thermodynamic experiments.