A technician heats sodium in four sealed containers. Each container initially contains 0.080 g of oxygen. The table shows the mass of sodium oxide formed when each reaction stops.
4Na+O2→2Na2O \mathrm{4Na + O_{2} \rightarrow 2Na_{2}O} 4Na+O2→2Na2O| Mass of sodium (g) | Mass of sodium oxide formed (g) |
|---|---|
| 0.092 | 0.124 |
| 0.184 | 0.248 |
| 0.276 | 0.310 |
| 0.368 | 0.310 |
The experiment using 0.184 g of sodium is repeated.
Which statement about the repeated experiment is correct?
Oxygen is in excess, so using more oxygen would increase the mass of sodium oxide.
Sodium is in excess, so using more oxygen would increase the mass of sodium oxide.
Oxygen is in excess, so using more sodium would increase the mass of sodium oxide.
Sodium is in excess, so using more sodium would increase the mass of sodium oxide.
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.