NSC / Matric The Chemical Industry — practice questions

1. Nitrogen from the air is useless to plants until it is fixed into a soluble compound. 2. The Haber process combines nitrogen gas with hydrogen gas. 3. The product of that combination is ammonia gas. 4. The ammonia is then the starting point for nitric acid, ammonium nitrate and urea. _Source: Siyavula Physical Sciences Grade 12 (Everything Science, CC BY 4.0), Chapter 14: The chemical industry_

1. Nitrogen and hydrogen react very slowly on their own, so a catalyst is needed. 2. The Haber process uses an iron catalyst. 3. It is run at high pressure, which favours the side with fewer gas molecules and so raises the yield of ammonia. 4. It is also run hot, because the forward reaction is exothermic and would otherwise be far too slow. 5. Platinum belongs to the Ostwald process and vanadium oxide to the Contact process, so neither fits here. _Source: Siyavula Physical Sciences Grade 12 (Everything Science, CC BY 4.0), Chapter 14: The chemical industry_

1. Ammonia is oxidised with oxygen over a platinum catalyst to give nitrogen monoxide and water. 2. The nitrogen monoxide is oxidised further to nitrogen dioxide. 3. The nitrogen dioxide is then absorbed in water, and that gives nitric acid. 4. Those three steps together are the Ostwald process. 5. Ammonium nitrate comes later, when that nitric acid is neutralised with more ammonia. _Source: Siyavula Physical Sciences Grade 12 (Everything Science, CC BY 4.0), Chapter 14: The chemical industry_