(a) describe the use of nitrogen, from air, and hydrogen, from cracking oil, in the manufacture of<br />ammonia<br />(b) state that some chemical reactions are reversible (e.g. manufacture of ammonia)<br />(c) *describe and explain the essential conditions for the manufacture of ammonia by the Haber<br />process<br />(d) describe the use of nitrogenous fertilisers in promoting plant growth and crop yield<br />(e) compare nitrogen content of salts used for fertilisers by calculating percentage masses<br />(f) describe eutrophication and water pollution problems caused by nitrates leaching from farm land and<br />explain why the high solubility of nitrates increases these problems<br />(g) describe the displacement of ammonia from its salts and explain why adding calcium hydroxide to<br />soil can cause the loss of nitrogen from added nitrogenous fertiliser
