Chemistry 9701/35 May June 2018 | Cambridge AS Level Past Papers With Mark Scheme

1. Preparation of Hydrated Sodium Carbonate Solution: Weighing hydrated sodium carbonate (Na2CO3.xH2O), dissolving in distilled water, and performing titration with hydrochloric acid to determine x in the hydrate formula.
2. Titration and Calculation of Moles: Performing titrations using methyl orange as an indicator, calculating the volume of HCl needed, and determining the moles of Na2CO3 in the solution.
3. Calculation of Molar Mass and x Value: Using titration data to calculate the relative formula mass of hydrated sodium carbonate and determining the value of x in Na2CO3.xH2O.
4. Effect of Using Sulfuric Acid: Exploring the potential impact on accuracy when substituting sulfuric acid for hydrochloric acid in the titration, and explaining the consequences of this change.
5. Group 2 Element Identification: Heating hydrated sulfate (YSO4.7H2O) to determine the relative atomic mass (Ar) of Y, calculating moles of water and anhydrous sulfate, and identifying the element Y.
6. Qualitative Analysis: Performing qualitative analysis to confirm the identity of Y by testing for specific ions, and interpreting results from heating, solubility, and reactions with different reagents.