6. Chemical reactions
A section of Chemistry, 0620
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Ammonia is an important chemical. Ammonia is manufactured by the Haber process. The reaction is reversible. What is the sign for a reversible reaction? State the essential conditions for the manufacture of ammonia by the Haber process starting from hydrogen and nitrogen. Include a chemical equation to show the reaction which occurs. Name one raw material which is a source of the hydrogen used in the Haber process. Ammonia is a base and reacts with sulfuricacid to form the salt, ammoniumsulfate. What is meant by the term base? Name the industrial process used to manufacture sulfuricacid. Write a chemical equation for the reaction between ammonia and sulfuricacid. When aqueous ammonia is added to aqueous iron(sulfate a green precipitate is seen. This green precipitate turns red-brown at the surface. Name the green precipitate. Suggest why the green precipitate turns red-brown at the surface. State what happens when an excess of aqueousammonia is added to the green precipitate. Ammonia reacts with oxygen as shown. 4NH3+ 5O24NO+ 6H2OCalculate the volume of oxygen at room temperature and pressure, in dm3, that reacts with 4.80 dm3 of ammonia.  volume = dm3 The chemical equation for the reaction can be represented as shown. H N H H + O O H O H + N O Use the bond energies in the table to calculate the energy change, in kJ / mol, which occurs when one mole of NH3 reacts. bond N–H O=O N=O O–H bond energy in kJ / mol ● ● Energy needed to break bonds.  kJ ● ● Energy released when bonds are formed.  kJ ● ● Energy change when one mole of NH3 reacts.  energy change = kJ / mol  
0620_w19_qp_42
THEORY
2019
Paper 4, Variant 2
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