Chemistry 9701/51 Oct Nov 2012 | Cambridge AS Level Past Papers With Mark Scheme

1. Analysis of lead oxides' chemical formulae using molar ratios of oxygen to lead atoms; calculation of ratios for PbO, PbO₂, and Pb₃O₄, and graphical representation of these relationships.

2. Experiment design for reducing lead oxides with hydrogen; apparatus setup for gas preparation, oxide heating, and safe handling of excess hydrogen with labeled diagram and stepwise methodology.

3. Determination of oxide identity; experimental steps for mass changes during reduction, minimum hydrogen volume calculations using stoichiometry and molar gas volume, and conclusion from results.

4. Hazard management in hydrogen reduction experiments; addressing risks of flammability and toxicity, and precautions like controlled environment and proper ventilation.

5. Validation of first-order kinetics for glucose hydrolysis; data processing for log10(a-x) vs. time, graph plotting, and identification of anomalous points with explanations for deviations.

6. Graph analysis for reaction rate; slope calculation for k-value determination, graphical representation of temperature effect on hydrolysis, and confirmation of the kinetic relationship log10(a-x) = kt.