Chemistry 0620 · IGCSE · Rate of reaction

Rate of reaction — practice question

A student studied how the reaction between dilute hydrochloric acid, HCl, and an excess of large pieces of marble, CaCO$_3$, progressed, using the apparatus shown.
(a(i))[1]

In what way does the graph’s shape show that the reaction rate fell as the reaction went on?

(a(ii))[1]

Why did the reaction rate fall as the reaction continued?

(a(iii))[1]

At how many seconds did the reaction end?

(b)[2]

Draw a graph on the grid that shows how the reaction progressed when the smaller pieces of marble were used.

(c)[5]

Describe and explain, in terms of particle collisions, the effect of using a higher temperature on the time needed for the reaction to finish.

Worked solution & mark scheme

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