A technician will prepare hydrogen using iron filings and dilute hydrochloric acid.
The reaction is:
Fe(s)+2HCl(aq)→FeCl2(aq)+H2(g)\mathrm{Fe(s) + 2HCl(aq) \rightarrow FeCl_{2}(aq) + H_{2}(g)}Fe(s)+2HCl(aq)→FeCl2(aq)+H2(g)
The flask will contain 0.672 g of iron and 40.0 cm340.0\,\mathrm{cm^{3}}40.0cm3 of 0.200 mol dm−30.200\,\mathrm{mol\,dm^{-3}}0.200moldm−3 hydrochloric acid.
The available gas syringes are:
| Gas syringe | Maximum capacity |
|---|---|
| A | 50 cm350\,\mathrm{cm^{3}}50cm3 |
| B | 100 cm3100\,\mathrm{cm^{3}}100cm3 |
| C | 250 cm3250\,\mathrm{cm^{3}}250cm3 |
| D | 500 cm3500\,\mathrm{cm^{3}}500cm3 |
(Relative atomic mass: Fe = 56. One mole of any gas occupies 24 000 cm324\,000\,\mathrm{cm^{3}}24000cm3 at room temperature and pressure.)
What is the smallest gas syringe that can collect all the hydrogen produced at room temperature and pressure?
100 cm3100\,\mathrm{cm^{3}}100cm3
250 cm3250\,\mathrm{cm^{3}}250cm3
500 cm3500\,\mathrm{cm^{3}}500cm3
50 cm350\,\mathrm{cm^{3}}50cm3
151 exam-style questions on Edexcel GCSE Chemistry 6.2 Quantitative analysis, covering 6.2.1 Concentration in mol dm⁻³ and titration calculations, 6.2.2 Percentage yield and why actual yield falls short, 6.2.3 Atom economy of a reaction, 6.2.4 Choosing a reaction pathway, and 6.2.5 Molar volume of gases and Avogadro's law. Each one has a worked solution and a mark scheme showing where the marks go.