The table shows the molecular formulae of some compounds found in a kitchen and a first aid kit.
| Compound | Molecular formula |
|---|---|
| ethanoic acid | C2H4O2\mathrm{C_{2}H_{4}O_{2}}C2H4O2 |
| glucose | C6H12O6\mathrm{C_{6}H_{12}O_{6}}C6H12O6 |
| ethanol | C2H6O\mathrm{C_{2}H_{6}O}C2H6O |
| hydrogen peroxide | H2O2\mathrm{H_{2}O_{2}}H2O2 |
Two of the compounds have the same empirical formula.
Name the two compounds and write their empirical formula.
Write the empirical formula of hydrogen peroxide.
Calculate the relative formula mass (MrM_{r}Mr) of glucose.
Relative atomic masses (ArA_{r}Ar): C = 12.0, H = 1.0, O = 16.0
Ethanol burns in oxygen. The balanced equation is shown.
C2H6O+3O2→2CO2+3H2O \mathrm{C_{2}H_{6}O + 3O_{2} \rightarrow 2CO_{2} + 3H_{2}O} C2H6O+3O2→2CO2+3H2OShow that the total relative formula mass of the reactants is the same as the total relative formula mass of the products.
51 exam-style questions on OCR GCSE Chemistry 2.1 Purity and separating mixtures, covering 2.1.1 Pure substances and melting point data, 2.1.2 Relative formula mass and empirical formula, 2.1.3 Formulations as useful mixtures, 2.1.4 Techniques for separating mixtures, and 2.1.5 Chromatography and Rf values. Each one has a worked solution and a mark scheme showing where the marks go.