How does the haber process affect the temperature

It also shows that at any given pressure ie following a vertical line up from the x-axis , as the temperature decreases , the yield of ammonia increases. In other words, as the temperature increases, the yield decreases.

There are fewer molecules on the right-hand side of the equation for the Haber process:. If the pressure is increased, the equilibrium position moves to the right, so the yield of ammonia increases. The rate of reaction also increases because the gas molecules are closer together, so successful collisions are more frequent.

However, the energy costs increase when higher pressures are used and the equipment becomes more expensive. Therefore, the choice of pressure is a compromise between yield and cost.

When the temperature is increased, the position of equilibrium moves in the endothermic direction to reduce the temperature. In the Haber process, the forwards reaction is exothermic , so the reverse reaction is endothermic. 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. By mixing one part ammonia to nine parts air with the use of a catalyst, the ammonia will get oxidized to nitric acid.

Jim Clark Chemguide. General Conditions of the Process The catalyst: The catalyst is actually slightly more complicated than pure iron. It has potassium hydroxide added to it as a promoter - a substance that increases its efficiency. The pressure : The pressure varies from one manufacturing plant to another, but is always high. You cannot go far wrong in an exam quoting atmospheres. This figure also varies from plant to plant. Composition 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.

According to Le Chatelier's Principle , this will be favored if you lower the temperature. The system will respond by moving the position of equilibrium to counteract this - in other words by producing more heat. To get as much ammonia as possible in the equilibrium mixture, you need as low a temperature as possible. Rate considerations : The lower the temperature you use, the slower the reaction becomes. A manufacturer is trying to produce as much ammonia as possible per day. The equipment is more expensive thicker pipes, stronger tanks etc and more energy is needed for high pressure work.

Temperature: A low temperature favours formation of the products, but will mean that reaction will happen slowly. A compromise temperature is used around o C. Pressure: A high pressure would favour the formation of the products and would help to give a fast rate of reaction but too high a pressure would have excessively high energy costs and expensive, thicker walled pipes and reactor would be needed so a compromise pressure is used around 2.

A finely divided iron catalyst is used to speed up the reaction, and the unconverted reactants are recirculated. Care is taken to ensure that the gas stream is clean dust can damage the catalyst and free of carbon monoxide which can damage the catalyst. Skip to main content. Search form.