Chemistry 5070 · O Level · Rate of reaction

Rate of reaction — practice question

Calcium carbonate undergoes reaction with dilute hydrochloric acid. $\text{CaCO}_3(s) + 2\text{HCl}(aq) \rightarrow \text{CaCl}_2(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$ A student investigates the way the rate of this reaction changes when the temperature is increased.
(a)[1]

State one variable, other than the concentration of hydrochloric acid and the temperature, that is expected to influence the rate of this reaction.

(b(i))[1]

Explain why this method does not maintain the reaction mixture at a constant temperature throughout the experiment.

(b(ii))[1]

Suggest how the method could be improved so the reaction mixture stays at a constant temperature for the whole experiment.

(c(i))[1]

Which experiment shows an anomalous reaction time?

(c(ii))[1]

What can the student do to find out whether the result is anomalous?

(c(iii))[1]

How does the rate of the reaction change as the reaction time gets shorter?

(c(iv))[1]

Which of the five experiments has the highest reaction rate?

(c(v))[1]

Describe how the reaction rate varies as the acid temperature changes.

(d)[1]

Another student carries out the reaction at $80^{\circ}\text{C}$. Why would measuring the reaction time accurately be difficult at this temperature?

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