5.23 describe the use of ammonia in the manufacture of nitric acid and fertilisers

5.23 •ammonium nitrate is a good fertiliser because it has nitrogen from two sources

                  •it is much more effective than organic substances to produce crops

5.22 understand how the cooing of the reaction mixture liquefies the ammonia produced and allows the unused hydrogen and nitrogen to be recirculated

 5.22 •ammonia is formed as a gas, but it liquifies i the condenser and is removed. The unused hydrogen and nitrogen are recycled, so nothing is wasted
                   •the catalyst speeds it all up

5.21 describe the manufacture of ammonia by the Haber process, including the essential conditions

5.21 •essential conditions for the Haber process:

                     •pressure: 200 atmospheres 

                     •temperature: 450 degrees celsius 

                     •catalyst: iron 

          •the iron catalyst make the reaction go faster, but doesn't affect the % yield 

          •set the pressure as high as possible for the best % yield, noting that it may be too

           expensive if it is set too high

          •lower the temperature for more % yield since the forward reaction is exothermic but if it’s too low, the rate will be too slow 

                     •450 degrees celsius is a compromise between maximum yield and speed of reaction

5.20 understand that nitrogen from air, and hydrogen form natural gas or the cracking of hydrocarbons, are used in the manufacture of ammonia

5.20 •nitrogen and hydrogen are needed to make ammonia 

        • N2(g) + 3H2(g) ------> 2NH3(g)

                                   <------

                   •we use the Haber process for this reaction

        •nitrogen is from the air (78%)

        •hydrogen comes from natural gas or cracking of hydrocarbons

                    •because it is reversible, not all will convert to ammonia, and so will reach dynamic equilibrium

5.19 explain that addition polymers are hard to dispose of as their inertness means that they do not easy biodegrade

5.19 •addition polymers are inert (don’t react easily) due to their strong carbon-carbon bond. They take a very very long time to biodegrade. Burning plastics releases toxic gases into the

         air, so it is best to reuse or recycle them

5.18 describe some uses for polymers, including poly(ethene) and poly)propene

5.18 •uses of poly(ethene) 

                   •packaging, containers, bottles, plastic bags and garden furniture

         •uses of poly(propene)

                    •food packaging, ropes and carpets 

5.17 deduce the structure of a monomer from the repeat unit of an addition polymer

 5.17 •this is the addition reaction. To go back, fold the carbon-to-carbon bond back in and you may draw brackets around the monomer with the ’n’ on the outside