Octane, C8H18\mathrm{C_{8}H_{18}}C8H18, is a hydrocarbon found in petrol. It burns completely in oxygen to form carbon dioxide and water.
The equation for this reaction is balanced using the smallest possible whole numbers. What is the number in front of O2\mathrm{O_{2}}O2?
17
25
34
50
230 exam-style questions on Edexcel GCSE Chemistry 1.1 Formulae, equations and hazards, covering 1.1.1 Formulae, word and balanced equations, 1.1.2 Balanced ionic equations, and 1.1.3 Hazard symbols and risk in practical work. Each one has a worked solution and a mark scheme showing where the marks go.