Chemistry 9701/34 Oct Nov 2018 | Cambridge AS Level Past Papers With Mark Scheme

1. Sodium Hydrogencarbonate Analysis by Titration: Using hydrochloric acid to titrate an impure sample of sodium hydrogencarbonate (NaHCO3), determining the mass and mole ratio of NaHCO3 in the sample.
2. Thermal Decomposition of Sodium Hydrogencarbonate: Investigating the thermal decomposition of sodium hydrogencarbonate to determine the percentage by mass of NaHCO3 in an impure sample by measuring mass loss during heating.
3. Calculation of Moles and Mass: Performing calculations to determine the number of moles of carbon dioxide, sodium hydrogencarbonate, and the mass of sodium hydrogencarbonate in the sample.
4. Improvement of Experimental Accuracy: Identifying improvements to increase accuracy in the experiment, including minimizing errors from environmental factors and ensuring complete reaction.
5. Chemical Testing of Impurities: Suggesting chemical tests to determine the presence of impurities in the sample, including confirming the composition of the unknown component X in the mixture.
6. Analysis of Experimental Results: Calculating the percentage by mass of NaHCO3 in the impure sample using both titration and thermal decomposition methods, and evaluating the accuracy of each method.