Chemistry 0620 · IGCSE · Reversible reactions and equilibrium

Reversible reactions and equilibrium — practice question

Sulfuric acid may be produced from sulfur, air and water as the raw materials. The manufacture is split into four stages. stage 1 changing sulfur to sulfur dioxide stage 2 changing sulfur dioxide to sulfur trioxide stage 3 changing sulfur trioxide to oleum, $\text{H}_2\text{S}_2\text{O}_7$ stage 4 changing oleum to sulfuric acid
(a(i))[1]

Explain how sulfur is changed into sulfur dioxide.

(a(ii))[1]

Write an equation for converting sulfur into sulfur dioxide.

(b(i))[1]

What does the symbol $\rightleftharpoons$ mean?

(b(ii))[1]

State the name of the catalyst for this reaction.

(b(iii))[1]

State why a catalyst is used.

(b(iv))[2]

If the temperature were raised above $450\,^{\circ}\text{C}$, what would happen to the quantity of sulfur trioxide made? Explain your answer.

(b(v))[1]

Suggest why a temperature below $450\,^{\circ}\text{C}$ is unsuitable.

(b(vi))[2]

If the pressure were increased to above 1-2 atmospheres, what would happen to the quantity of sulfur trioxide made? Explain your answer.

(c(i))[1]

What must be added to sulfur trioxide to make oleum?

(c(ii))[1]

Write a chemical equation for turning sulfur trioxide into oleum.

(d(i))[1]

What is added to oleum so that sulfuric acid is produced?

(d(ii))[1]

Write a chemical equation for turning oleum into sulfuric acid.

(e)[1]

State one use of sulfuric acid.

(f(i))[1]

What does the term strong acid mean?

(f(ii))[2]

Describe how you could show that a $1\,\text{mol dm}^{-3}$ solution of benzenesulfonic acid is a strong acid.

(f(iii))[2]

Write an equation for the reaction between benzenesulfonic acid and sodium carbonate, $\text{Na}_2\text{CO}_3$.

Worked solution & mark scheme

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