Chemistry 9701/51 May June 2010 | Cambridge AS Level Past Papers With Mark Scheme

1. Neutralization Experiment Setup: Volume selection of NaOH for neutralization with H₂SO₄, temperature changes recorded, and calculation of expected temperature graph for the neutralization reaction.
2. Experiment Variables: Independent, dependent, and controlled variables for accurate enthalpy change determination, including identification of apparatus for measuring the independent variable.
3. Risk Management: Identifying and mitigating risks associated with the plastic cup and NaOH, along with suggested precautions for their safe handling.
4. Heat Energy Calculation: Calculation of total heat energy produced during the neutralization reaction using temperature changes.
5. Enthalpy Change of Neutralization: Calculation of ΔHneutralisation from the measured heat energy, ensuring conversion to kJ/mol with proper sign and formula.
6. Mixture Properties: Boiling points of mixtures of propan-1-ol and propan-2-ol, and ethanol and cyclohexane, including identification of anomalies, completion of tables, and graphing of temperature against composition.
7. Mixture Characteristics: Interpretation of graphs to determine whether the ethanol-cyclohexane mixture is endothermic or exothermic, and identification of intermolecular forces involved.
8. Magnesium Oxide Experiment: Investigating magnesium oxide formula determination by heating magnesium ribbon in a crucible, including completing tables with mass data, plotting results, and analyzing anomalies in student data.
9. Result Deviations: Identifying possible experimental errors or risks, such as incorrect magnesium mass or water contamination in magnesium oxide, affecting the formula determination.