GCSE AQA Chemistry Rate of Reaction: A student investigated the rate

Question

A student investigated the rate of reaction between calcium carbonate (marble chips) and hydrochloric acid.

The student used the apparatus shown in Figure 1.

The student:
- recorded the volume of gas collected every 5 seconds
- repeated the experiment using hydrochloric acid at different temperatures.

The equation for the reaction is:

CaCO₃(s) + 2 HCl(aq) ⟶ CaCl₂(aq) + H₂O(l) + CO₂(g)

1 (a) The student plotted results for the hydrochloric acid at 20 °C and 40 °C on a graph.

Figure 2 shows the student’s graph.

Use information from Figure 2 to answer these questions.

1 (a) (i) State one conclusion the student could make about the effect of temperature on the rate of the reaction.

1 (a) (iii) For the hydrochloric acid at 60 °C the student had collected 30 cm³ after 15 seconds.
Calculate the average rate of reaction from 0 to 15 seconds.

1 (b) The student then investigated how the surface area of marble chips affected the rate of reaction.

1 (b) (i) Which two variables should the student keep constant?
Tick (✓) two boxes.

Amount of water in the trough
Concentration of acid
Mass of marble chips
Size of marble chips
Volume of measuring cylinder

1 (b) (ii) Explain, in terms of particles and collisions, the effect that increasing the surface area of the marble chips has on the rate of reaction.

1 (c) Calcium carbonate is a catalyst for the industrial production of biodiesel.
Give one reason why using a catalyst reduces costs.

A student investigated the rate of reaction between calcium carbonate (marble chips) and hydrochloric acid - AQA - GCSE Chemistry - Question 1 - 2015 - Paper 2

Worked Solution & Example Answer:A student investigated the rate of reaction between calcium carbonate (marble chips) and hydrochloric acid - AQA - GCSE Chemistry - Question 1 - 2015 - Paper 2

State one conclusion the student could make about the effect of temperature on the rate of the reaction.

For the hydrochloric acid at 60 °C the student had collected 30 cm³ after 15 seconds. Calculate the average rate of reaction from 0 to 15 seconds.

Which two variables should the student keep constant?

Explain, in terms of particles and collisions, the effect that increasing the surface area of the marble chips has on the rate of reaction.

Give one reason why using a catalyst reduces costs.

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