QUESTION 2 Ammonium nitrate is an important fertiliser m…
QUESTION 2 Ammonium nitrate is an important fertiliser made by the acid-base reaction between ammonia and nitric acid. 2.1 Write an equation for the production of ammonium nitrate from ammonia and nitric acid. The ammonia for this reaction is produced by the Haber process and the nitric acid is produced by oxidation of ammonia. The Haber process involves a reaction between nitrogen and hydrogen at a temperature of 450 °C and a pressure of 20 000 kPa. At a higher reaction temperature, the rate of production of ammonia would be greater N2(g) + 3H2(g) < == >2NH3 ΔH = –92 kJ mol–1 The Boltzmann distribution curve shows the distribution of energies in a mixture of nitrogen and hydrogen at 450 °C. Right-click on the button to open the data booklet in a new tab. 2.2 Sketch a second line onto the axes above to show the distribution of energies in the same mixture of gases at a higher temperature. 2.3 With reference to the two curves, explain why the rate of production of ammonia would be greater at a higher temperature. 2.4 Add a suitable label to the horizontal axis above and use it to explain why a catalyst is used in the Haber process. 2.5 Explain why a higher temperature is not used despite the fact that it would increase the rate of production of ammonia. 2.6 The first stage in the production of nitric acid involves the reaction of ammonia with oxygen to form nitrogen monoxide, NO, and water. Suggest an equation for this reaction and use oxidation numbers to show that it is a redox reaction. 2.7 Draw a dot-and-cross diagram of the ammonium ion. Show the outer electrons only. Use the following key for your electrons. • electrons from nitrogen. x electrons from hydrogen reaction. 2.8 State the shape of an ammonium ion and give the H–N–H bond angle. shape …. bond angle ….. 2.9 State and explain the problems that arise from the overuse of ammonium nitrate fertiliser when the excess is washed into rivers.