A student adds different masses of magnesium ribbon to separate 50.0 cm350.0\,\mathrm{cm^{3}}50.0cm3 portions of the same dilute hydrochloric acid. The student measures the total volume of hydrogen made each time.
Mg+2HCl→MgCl2+H2 \mathrm{Mg + 2HCl \rightarrow MgCl_{2} + H_{2}} Mg+2HCl→MgCl2+H2| Mass of magnesium (g) | Volume of hydrogen (cm3\mathrm{cm^{3}}cm3) |
|---|---|
| 0.10 | 99 |
| 0.20 | 198 |
| 0.30 | 240 |
| 0.40 | 240 |
| 0.50 | 240 |
Which statement about the limiting reactant is correct?
The acid is limiting in all five experiments.
Magnesium is limiting in all five experiments.
The acid is limiting with 0.10 g and 0.20 g; magnesium is limiting with 0.30 g and above.
Magnesium is limiting with 0.10 g and 0.20 g; the acid is limiting with 0.30 g and above.
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.