A student investigated how temperature affects the rate of reaction between magnesium carbonate and dilute hydrochloric acid - AQA - GCSE Chemistry - Question 8 - 2018 - Paper 2

To plot the data:

1. On the x-axis (Time in seconds), mark the time intervals from the table: 0, 20, 40, 60, 80, 100, 120, 140.
2. On the y-axis (Loss of mass in grams), mark the corresponding mass loss values: 0.00, 0.26, 0.48, 0.67, 0.82, 0.91, 0.96, 0.99.
3. Plot each point and ensure all eight points are accurately represented within the allowed tolerance.
4. Draw a line of best fit through the points.

To find the rate of reaction when the loss of mass is 0.95 g, first draw a tangent to the curve on Figure 7 at the point where loss of mass equals 0.95 g.

1. Identify the point of 0.95 g on the y-axis and find the corresponding time on the x-axis where the loss reaches this value.

2. Use the tangent's slope:

   $ext{Rate} = \frac{\text{Change in Mass}}{\text{Change in Time}}$

To calculate the change in mass and time from the tangent: 3. Record the values for mass loss against time from the tangent and input them into the equation to find the rate. 4. Round the final answer to 2 significant figures.