Nitrogen, N2, is an inert gas that makes up 78% of the Earth's atmosphere. Explain why nitrogen is inert.

1. (a)(i)Nitrogen, N2, is an inert gas that makes up 78% of the Earth's atmosphere. Explain why nitrogen is inert.[2]
2. (a)(ii)Draw a 'dot-and-cross' diagram of a nitrogen molecule. Show outer electrons only.[1]
3. (b)(i)Nitrogen, N2, and oxygen, O2, react together in the air during lightning strikes to form nitrogen monoxide, NO. Explain why the reaction of N2 and O2 occurs during lightning strikes.[1]
4. (b)(ii)Write two equations to suggest how the NO formed reacts further to create nitric acid, HNO3. 1 2[2]
5. (c)Nitrate fertilisers are used to provide nitrogen for plant growth. Uncontrolled use of these can cause a reduction in animal and plant life in natural water supplies. Explain how uncontrolled use of nitrate fertilisers can cause this problem.[3]
6. (d)(i)Some soils have compounds such as ammonium nitrate, calcium carbonate and calcium hydroxide added to them. Suggest why calcium hydroxide is added to some soils.[1]
7. (d)(ii)When calcium hydroxide reacts with compounds containing the ammonium ion, NH4+, a gas is produced. State the identity of this gas and explain why the reaction occurs. gas explanation[2]
8. (d)(iii)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 observed in this reaction.[2]
9. (d)(iv)Calcium nitrate decomposes at a higher temperature than calcium ammonium nitrate. Write an equation for the thermal decomposition of calcium nitrate.[1]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.