Aluminium reacts with oxygen, O2\mathrm{O_2}O2, to form aluminium oxide, Al2O3\mathrm{Al_2O_3}Al2O3.
The table shows the masses measured when the reactants are in exactly the correct proportions.
| Substance | Mass in g |
|---|---|
| Aluminium | 5.40 |
| Oxygen | 4.80 |
| Aluminium oxide | 10.20 |
Relative atomic masses (ArA_rAr): Al = 27.0, O = 16.0
Use the masses in the table to calculate the smallest whole-number ratio of moles of Al:O2:Al2O3\mathrm{Al:O_2:Al_2O_3}Al:O2:Al2O3.
A second sample of 8.10 g of aluminium reacts with excess oxygen.
Calculate the mass of aluminium oxide formed.
134 exam-style questions on OCR GCSE Chemistry 3.1 Introducing chemical reactions, covering 3.1.1 Writing formulae and balanced chemical equations, 3.1.2 Formulae of compounds from ions, and state symbols, 3.1.3 Conservation of mass and observed changes in mass, 3.1.4 Half equations and balanced ionic equations, 3.1.5 The mole and the Avogadro constant, and 3.1.6 Stoichiometry, limiting reactants and reacting masses. Each one has a worked solution and a mark scheme showing where the marks go.