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, mark each pair of values from Table 5 on Figure 6. The x-axis represents 'Time in seconds' and the y-axis represents 'Loss of mass in grams'. Ensure all eight points are plotted accurately, using a tolerance of ± half a small square if necessary. Draw a line of best fit that represents the trend of the data.

To determine the rate of reaction, first draw a tangent line at the point where the loss of mass reaches 0.95 g on Figure 7. Use two distinct points on this tangent line to calculate the slope. The slope is calculated as follows:

1. Identify the points on the tangent line, for example, (x1, y1) and (x2, y2).

2. The rate of reaction is given by:

   $ext{Rate} = \frac{\text{change in y}}{\text{change in x}} = \frac{y_2 - y_1}{x_2 - x_1}$

3. Substitute the y-values (loss of mass) and x-values (time) from the points identified.

4. Provide the final answer rounded to 2 significant figures.