Which equation is correctly balanced?
Ca(OH)2+HNO3→Ca(NO3)2+2H2O\mathrm{Ca(OH)_{2} + HNO_{3} \rightarrow Ca(NO_{3})_{2} + 2H_{2}O}Ca(OH)2+HNO3→Ca(NO3)2+2H2O
Al2(SO4)3+6NaOH→2Al(OH)3+3Na2SO4\mathrm{Al_{2}(SO_{4})_{3} + 6NaOH \rightarrow 2Al(OH)_{3} + 3Na_{2}SO_{4}}Al2(SO4)3+6NaOH→2Al(OH)3+3Na2SO4
Fe2(SO4)3+2BaCl2→2FeCl3+3BaSO4\mathrm{Fe_{2}(SO_{4})_{3} + 2BaCl_{2} \rightarrow 2FeCl_{3} + 3BaSO_{4}}Fe2(SO4)3+2BaCl2→2FeCl3+3BaSO4
(NH4)2SO4+NaOH→Na2SO4+2NH3+H2O\mathrm{(NH_{4})_{2}SO_{4} + NaOH \rightarrow Na_{2}SO_{4} + 2NH_{3} + H_{2}O}(NH4)2SO4+NaOH→Na2SO4+2NH3+H2O
55 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.