Railway workers join steel rails together using the thermite reaction.
A mixture of aluminium powder and iron(III) oxide, Fe₂O₃, is lit. The reaction makes molten iron and aluminium oxide, Al₂O₃.
Relative atomic mass (Ar): Al = 27.0, Fe = 55.8, O = 16.0
Write the balanced symbol equation for the thermite reaction.
One thermite mixture contains 3.20 kg of iron(III) oxide.
Calculate the maximum mass of iron that can be made.
Give your answer in kg to 3 significant figures.
Maximum mass of iron = ...... kg
The mixture also contains 1.20 kg of aluminium.
Show that aluminium is in excess and calculate the mass of aluminium left over at the end of the reaction.
Mass of aluminium left over = ...... g
Suggest why the mixture is made with aluminium in excess.
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.