The fixation of nitrogen by e. The idea of using optimum conditions has been described in detail in section 3a. Ideally it would be great to develop catalyst as powerful as enzymes to 'fix' the nitrogen at room temperature and atmospheric pressure, thereby saving on energy and more costly reactor technology making the overall process cheaper and more efficient. Perhaps genetically modified cells can be developed with more powerful enzymes?
Since huge quantities of ammonia are manufactured world-wide, using lots of energy AND oil based hydrocarbons, how sustainable is the Haber process?
The hydrogen is made from methane, a non-renewable fossil fuel resource. This is a finite resource, though the nitrogen comes in abundance from the air and would never run out! There are no waste products because there is only one product possible no by-products and even the unreacted gases are recycled. The process is costly in terms of energy needs to maintain a reactor temperature of o C and atmosphere pressure and these process conditions come with a range of health and safety issues to do with high temperatures and pressures - chemical plants are always potentially dangerous unless managed very carefully.
Despite, some negative issues mentioned, making ammonia is very profitable because of the huge and increasing world-wide demand for food, especially growing it rapidly with high crop yields.
Doc Brown's. Higher tier harder multiple choice QUIZ on ammonia, nitric acid and fertilisers etc. WJEC gcse science chemistry why is a catalyst need to make ammonia? The Haber Process is used in the manufacturing of ammonia from nitrogen and hydrogen, and then goes on to explain the reasons for the conditions used in the process.
The process combines nitrogen from the air with hydrogen derived mainly from natural gas methane into ammonia. The reaction is reversible and the production of ammonia is exothermic. The proportions of nitrogen and hydrogen: The mixture of nitrogen and hydrogen going into the reactor is in the ratio of 1 volume of nitrogen to 3 volumes of hydrogen. Avogadro's Law says that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
That means that the gases are going into the reactor in the ratio of 1 molecule of nitrogen to 3 of hydrogen. That is the proportion demanded by the equation. In some reactions you might choose to use an excess of one of the reactants. You would do this if it is particularly important to use up as much as possible of the other reactant - if, for example, it was much more expensive.
That does not apply in this case. There is always a down-side to using anything other than the equation proportions. If you have an excess of one reactant there will be molecules passing through the reactor which cannot possibly react because there is not anything for them to react with.
This wastes reactor space - particularly space on the surface of the catalyst. According to Le Chatelier's Principle, if you increase the pressure the system will respond by favoring the reaction which produces fewer molecules. That will cause the pressure to fall again.
In order to get as much ammonia as possible in the equilibrium mixture, you need as high a pressure as possible. If the pressure were any higher than this, it would increase equipment costs significantly as the equipment would have to be a lot stronger to contain the higher pressure. Higher pressure also increases the risk of explosions occurring. This, combined with the use of the hot iron catalyst, means that a good yield of ammonia is produced constantly. Since the hydrogen and nitrogen is recycled, very little of the reactants are wasted.
These reaction conditions are not the best in terms of the yield but balance a decent yield with a decent rate of reaction and a reasonable production cost.
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