Chemistry 5070 · O Level · Rate of reaction

Rate of reaction — practice question

Cerium is a metal whose relative atomic mass is 140. Cerium powder undergoes reaction with sulfuric acid. $2\text{Ce}(s)+3\text{H}_2\text{SO}_4(aq)\rightarrow \text{Ce}_2(\text{SO}_4)_3(aq)+3\text{H}_2(g)$.
(a)[2]

Describe and explain how the rate of this reaction changes when the concentration of sulfuric acid is decreased. All other conditions stay the same.

(b)[1]

Describe and explain how the rate of this reaction changes when large pieces of cerium are used instead of cerium powder. All other conditions stay the same.

(c)[2]

The reaction of cerium with sulfuric acid is exothermic. Complete the energy profile diagram so it shows the enthalpy change for this reaction.

(d)[3]

Calculate the maximum volume of hydrogen, in $\text{dm}^3$, obtained when $12.6\,\text{g}$ of cerium reacts with excess sulfuric acid at room temperature and pressure. [$A_r: \text{Ce},140$]

(e)[2]

Cerium carbonate has the formula $\text{Ce}_2(\text{CO}_3)_3$. Calculate the percentage by mass that is due to cerium in cerium carbonate.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Fewer acid particles per unit volume

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