A gas-supply technician needs at least 14.0 g of ethene, C2H4\mathrm{C_{2}H_{4}}C2H4. Use Mr(C2H4)=28M_r(\mathrm{C_{2}H_{4}}) = 28Mr(C2H4)=28. Four cylinders are available.
| Cylinder | Amount of ethene |
|---|---|
| A | 0.25 mol |
| B | 0.50 mol |
| C | 0.75 mol |
| D | 1.00 mol |
Which cylinder contains the smallest amount of ethene that provides at least 14.0 g?
Cylinder A (0.25 mol0.25\ \mathrm{mol}0.25 mol)
Cylinder C (0.75 mol0.75\ \mathrm{mol}0.75 mol)
Cylinder B (0.50 mol0.50\ \mathrm{mol}0.50 mol)
Cylinder D (1.00 mol1.00\ \mathrm{mol}1.00 mol)
142 exam-style questions on Edexcel GCSE Chemistry 2.6 Calculations involving masses, covering 2.6.1 Relative formula mass and percentage composition, 2.6.2 Empirical and molecular formulae, 2.6.3 Conservation of mass, 2.6.4 Reacting masses and concentration in g dm⁻³, 2.6.5 The mole and the Avogadro constant, and 2.6.6 Limiting reactants and stoichiometry. Each one has a worked solution and a mark scheme showing where the marks go.