Iron powder is heated in a sealed vessel containing oxygen. Initially, the vessel contains 11.16 g of iron and 3.20 g of oxygen.
4Fe+3O2→2Fe2O3 \mathrm{4Fe + 3O_2 \rightarrow 2Fe_2O_3} 4Fe+3O2→2Fe2O3Relative atomic mass (ArA_rAr): Fe = 55.8 O = 16.0
The reaction is allowed to finish. Which description of the vessel contents at the end is correct?
7.98 g of iron(III) oxide has formed, with oxygen left over.
16.0 g of iron(III) oxide has formed, with oxygen left over.
5.32 g of iron(III) oxide has formed, with iron left over.
10.6 g of iron(III) oxide has formed, with iron left over.
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.