Explain the reason nitrogen is inert.
Draw a ‘dot-and-cross’ diagram of a nitrogen molecule. Show only outer-shell electrons.
Nitrogen, $\text{N}_2$, and oxygen, $\text{O}_2$, react together in the air during lightning strikes to form nitrogen monoxide, $\text{NO}$. Explain why the reaction of $\text{N}_2$ and $\text{O}_2$ takes place during lightning strikes.
Write two equations to show how the $\text{NO}$ formed goes on to make nitric acid, $\text{HNO}_3$.
Nitrate fertilisers supply nitrogen for plant growth. Uncontrolled use of these can reduce the amount of animal and plant life in natural water supplies. Explain how uncontrolled use of nitrate fertilisers can lead to this problem.
Suggest why calcium hydroxide is added to some soils.
When calcium hydroxide reacts with compounds containing the ammonium ion, $\mathrm{NH}_4^+$, a gas is produced. State the identity of this gas and explain why the reaction happens.
Another fertiliser, calcium ammonium nitrate, is formed when solid calcium carbonate is added to a mixture of aqueous ammonium nitrate and dilute nitric acid. Suggest what would be seen in this reaction.
Calcium nitrate decomposes at a higher temperature than calcium ammonium nitrate. Write an equation for the thermal decomposition of calcium nitrate.