Chemistry 0620 · IGCSE · Fertilisers

Fertilisers — practice question

This question deals with nitrogen and several of its compounds.
(a(i))[1]

State the proportion of nitrogen present in clean, dry air.

(a(ii))[1]

State where the hydrogen for the Haber process comes from.

(a(iii))[2]

Complete the dot-and-cross diagram in Fig. 3.1 for a molecule of ammonia. Show only the electrons in the outer shell.

(a(iv))[5]

Write the chemical equation for the reaction in the Haber process, then give the usual reaction conditions. Include units where they are needed.

(b(i))[1]

Suggest which element below is most likely to act as the catalyst. Circle your choice. calcium, lead, platinum, sodium, sulfur

(b(ii))[2]

State the oxidation number of nitrogen in $\text{NH}_3$. State the oxidation number of nitrogen in NO.

(b(iii))[1]

Use your answer to (ii) to explain whether the nitrogen in ammonia is oxidised or reduced.

(b(iv))[4]

Complete Table 3.1 with the words increases, decreases or no change.

(b(v))[3]

A lower temperature makes the rate of the forward reaction fall. Explain, using collision theory, why the reaction rate is slower at the lower temperature.

(c)[1]

Balance the symbol equation for this reaction. $\ldots\ldots\text{NO} + \ldots\ldots\text{O}_2 + \ldots\ldots\text{H}_2\text{O} \rightarrow \ldots\ldots\text{HNO}_3$

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