Chemistry 0620 · IGCSE · Rate of reaction

Rate of reaction — practice question

A student investigated how the volume of gas changed as a reaction went on after adding a small mass of powdered barium carbonate to an excess of 0.1 mol/dm$^3$ hydrochloric acid. The reaction between barium carbonate and dilute hydrochloric acid produces carbon dioxide gas, and a graph was then plotted from the results.
(a)[1]

State the two pieces of apparatus needed to make the measurements shown on the graph.

(b)[2]

On the axes below, sketch a graph to show how the rate of reaction changes as the reaction goes on. Take the initial rate of reaction to be the point at X.

(c)[3]

Calculate the mass, in grams, of barium carbonate used. $\text{BaCO}_3 + 2\text{HCl} \rightarrow \text{BaCl}_2 + \text{H}_2\text{O} + \text{CO}_2$

(d)[2]

On the grid, draw the graph you would expect if the same mass of barium carbonate were added as large lumps rather than as a powder. All other conditions stay the same as in the original experiment. Explain why your graph differs from the original graph.

(e)[4]

On the grid, draw the graph expected if the concentration of dilute hydrochloric acid is changed from 0.1 mol/dm$^3$ to 0.2 mol/dm$^3$. All other conditions stay the same as in the original experiment. Explain, in terms of particles, why your graph differs from the original graph.

(f)[1]

Deduce the volume of gas formed at room temperature and pressure, in cm$^3$, in this experiment.

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