Hydrogen reacts with oxygen to form water.
Which equation for this reaction conserves all the hydrogen and oxygen atoms?
2H2+O2→2H2O2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}2H2+O2→2H2O
2H2+2O2→H2O2\text{H}_2 + 2\text{O}_2 \rightarrow \text{H}_2\text{O}2H2+2O2→H2O
H2+O2→2H2O\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}H2+O2→2H2O
H2+2O2→2H2O\text{H}_2 + 2\text{O}_2 \rightarrow 2\text{H}_2\text{O}H2+2O2→2H2O
93 exam-style questions on AQA GCSE Chemistry 1.1 A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes, covering 1.1.1a Atoms, elements and compounds, 1.1.1b Half equations and ionic equations, 1.1.2 Mixtures, 1.1.3 The development of the model of the atom (common content with physics), 1.1.4 Relative electrical charges of subatomic particles, 1.1.5 Size and mass of atoms, 1.1.6 Relative atomic mass, and 1.1.7 Electronic structure. Each one has a worked solution and a mark scheme showing where the marks go.