A student follows a reaction by measuring the mass of gas lost from a flask. The mass lost is plotted against time, giving a curve. A tangent is drawn to the curve at 30 s. Two points on this tangent are shown in the table.
| Time in s\text{s}s | Mass lost in g\text{g}g |
|---|---|
| 10 | 1.0 |
| 50 | 2.8 |
How can the rate of reaction at 30 s be calculated?
By calculating 2.850\dfrac{2.8}{50}502.8
By calculating 2.8−1.030\dfrac{2.8-1.0}{30}302.8−1.0
By calculating 50−102.8−1.0\dfrac{50-10}{2.8-1.0}2.8−1.050−10
By calculating 2.8−1.050−10\dfrac{2.8-1.0}{50-10}50−102.8−1.0
127 exam-style questions on AQA GCSE Chemistry 6.1 Rate of reaction, covering 6.1.1a Calculating rates of reactions, 6.1.1b Gradient of a tangent as rate, 6.1.2 Factors which affect the rates of chemical reactions, 6.1.3 Collision theory and activation energy, and 6.1.4 Catalysts. Each one has a worked solution and a mark scheme showing where the marks go.