Chemistry 5070 · O Level · Rate of reaction

Rate of reaction — practice question

A learner uses the setup shown to explore how marble $(\text{CaCO}_3)$ reacts with hydrochloric acid.
(a)[2]

Fill in the table by working out the total mass change at each time for both experiments.

(b)[1]

Construct the equation for the reaction of calcium carbonate with hydrochloric acid.

(c)[1]

Suggest why the mass of the flask and its contents falls as the reaction continues.

(d)[3]

On the grid, plot the points for each experiment, draw a smooth curve through each data set and label the curves.

(e(i))[1]

Using your graph, what total change in mass is shown in experiment 1 after $75$ seconds?

(e(ii))[1]

Using your graph, what is the mass of the flask and its contents in experiment 2 after $45$ seconds?

(f)[2]

State and explain how using powdered marble instead of marble lumps in experiment 2 changes the reaction rate.

(g)[2]

Calculate the mass of marble left after reaction with $30.0\,\text{cm}^3$ of $1.20\,\text{mol dm}^{-3}$ hydrochloric acid.

Worked solution & mark scheme

This 13-mark question has a full step-by-step worked solution and mark scheme. One marking point: 0.63, 0.73, 0.81 and 0.81

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