Ammonia burns in oxygen to form nitrogen and water.
NH3+O2→N2+H2O \mathrm{NH_{3} + O_{2} \rightarrow N_{2} + H_{2}O} NH3+O2→N2+H2OBalance the equation, using the smallest whole-number balancing numbers.
A student writes this equation.
2NH2+O2→N2+2H2O \mathrm{2NH_{2} + O_{2} \rightarrow N_{2} + 2H_{2}O} 2NH2+O2→N2+2H2OExplain why this is not a correct way to balance the equation in part (a).
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.