Chemistry 9701 · AS & A Level · Nitrogen and sulfur

Nitrogen and sulfur — practice question

Nitric acid can be produced by a process with 3 stages.
(a)[1]

Write an equation that shows the reaction taking place in stage 1.

(b)[1]

Draw a ‘dot-and-cross’ diagram to show how the outer electrons are arranged in a molecule of ammonia.

(c(i))[2]

In the boxes, give the oxidation numbers of nitrogen in the nitrogen-containing species for the reaction in stage 3, $\text{3NO}_2 + \text{H}_2\text{O} \rightarrow 2\text{HNO}_3 + \text{NO}$.

(c(ii))[2]

Explain why the reaction in stage 3 is called a disproportionation reaction. Include reference to electron transfer in your answer.

(d)[2]

The release of nitrogen monoxide into the atmosphere leads to atmospheric pollution. State and explain the effect of nitrogen monoxide gas when it comes into contact with moist air.

(e)[3]

The nitric acid formed in stage 3 can then be reacted with ammonia to make ammonium nitrate. Stage 3: $3\text{NO}_2 + \text{H}_2\text{O} \rightarrow 2\text{HNO}_3 + \text{NO}$. $\text{NH}_3 + \text{HNO}_3 \rightarrow \text{NH}_4\text{NO}_3$. Calculate the volume of nitrogen dioxide, measured at room temperature and pressure, needed to make $40$ tonnes of ammonium nitrate. [$1$ tonne $= 1000\,\text{kg}$]. Show your working.

(f)[1]

State one use of ammonium nitrate.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: Balanced equation $\mathrm{4NH_3 + 5O_2 \rightarrow 4NO + 6H_2O}$

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