Chemistry 0620 · IGCSE · Rate of reaction

Rate of reaction — practice question

A student studies the reaction between large pieces of magnesium and dilute hydrochloric acid at 20^{\circ}C. The magnesium is in excess.
(a(i))[1]

Deduce the volume of hydrogen gas given off after 30 seconds.

(a(ii))[2]

The student carries out the experiment again using smaller pieces of magnesium. The mass of magnesium used is unchanged and magnesium is still in excess. All other conditions remain unchanged. Draw a line on the grid in Fig. 6.1 to show the volume of hydrogen gas released.

(b(i))[1]

The student repeats the experiment at a higher temperature of 35^{\circ}C. Describe how the rate changes when 35^{\circ}C is used.

(b(ii))[1]

The student repeats the experiment using a lower concentration of acid. Describe how the rate changes.

(c(i))[2]

Hydrochloric acid reacts with lithium hydroxide. Complete the word equation shown below: hydrochloric acid + lithium hydroxide → ................. + .................

(c(ii))[1]

Choose the word from the list that most accurately describes this reaction: addition, decomposition, neutralisation, oxidation.

(c(iii))[1]

State the colour seen when thymolphthalein is dissolved in aqueous sodium hydroxide.

Worked solution & mark scheme

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