Chemistry 5070 · O Level · Separation and purification

Separation and purification — practice question

Some power stations rely on the combustion of fossil fuels.
(a(i))[1]

Some power stations burn diesel oil as a fuel. One compound in diesel oil has the formula C$_{12}$H$_{26}$. Construct the symbol equation to show complete combustion of C$_{12}$H$_{26}$.

(a(ii))[1]

The complete combustion of C$_{12}$H$_{26}$ produces an air pollutant. State one adverse effect of this pollutant.

(a(iii))[3]

Explain how diesel oil can be separated from petroleum.

(b(i))[1]

Calcium carbonate powder is used to remove sulfur dioxide from the emissions from a power station. State one adverse effect of sulfur dioxide as an air pollutant.

(b(ii))[1]

When one mole of sulfur dioxide reacts with one mole of calcium carbonate, one mole of carbon dioxide and only one other product are formed. Suggest the formula of this product.

(b(iii))[2]

State and explain how increasing the temperature affects the rate of this reaction.

(b(iv))[2]

Calcium carbonate powder is replaced by lumps of calcium carbonate. State and explain the effect of this change on the rate of this reaction.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: C₁₂H₂₆ + 18½O₂ → 12CO₂ + 13H₂O.

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