A laboratory technician uses a titration to check the concentration of an alkali solution. The results are shown.
| Titration | Titre / cm3\mathrm{cm^3}cm3 |
|---|---|
| Rough | 23.20 |
| 1 | 22.40 |
| 2 | 22.65 |
| 3 | 22.70 |
Which titres should be used to calculate the mean titre?
Titres 2 and 3 only
The rough titre and titres 2 and 3
Titres 1, 2 and 3
Titres 1 and 2 only
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.