Ammonia and Haber Process
7.4
Case Study: The Haber Process:
Ammonia for Food and Bombs
From: Eros Wang
To: Ms. Irumekhai
Date: March 30, 2012
1. Suggest five factors that could affect the production of ammonia in the Haber process. Explain the effect of each factor, using rate theory.
The Haber process itself is a delicate balancing act because of all the factors that affect the yield of ammonia. In the Haber process, the nitrogen, hydrogen and ammonia are in equilibrium. So five factors that affect the production of ammonia would be:
a) Temperature. The reaction is an exothermic reaction, meaning it produces heat. The higher the temperature in the reaction chamber, the less ammonia is produced, as the equilibrium shifts to the right to counteract the heat as it is an exothermic reaction, producing more hydrogen and nitrogen gas. But this doesn’t mean that the rate of reaction will be slower. In general, increasing the temperature always increases the rate of reaction.
b) Pressure. If the pressure of the system is increased, the hydrogen and nitrogen gas molecules are compressed together, and the equilibrium shifts to the right, forming ammonia molecules. Increased pressure also increases the reaction rate, as the gas molecules are more concentrated and closer together.
c) Catalyst. To increase the rate of reaction, a catalyst is used. In the Haber process, the catalyst used is a finely ground porous iron powder, with a large surface area. It absorbs the nitrogen and hydrogen gases and they react with each other on the catalyst’s surface, producing ammonia.
d) Concentration of the reactants. Increasing the concentration of the reactants means the equilibrium shifts to the right producing more ammonia gases. By increasing the concentration of the reactants also means that collisions are suddenly much more frequent for the forward reaction. This increases the forward rate significantly.
e) Removing the product. If the product (ammonia) is removed, causing the equilibrium
Case Study: The Haber Process:
Ammonia for Food and Bombs
From: Eros Wang
To: Ms. Irumekhai
Date: March 30, 2012
1. Suggest five factors that could affect the production of ammonia in the Haber process. Explain the effect of each factor, using rate theory.
The Haber process itself is a delicate balancing act because of all the factors that affect the yield of ammonia. In the Haber process, the nitrogen, hydrogen and ammonia are in equilibrium. So five factors that affect the production of ammonia would be:
a) Temperature. The reaction is an exothermic reaction, meaning it produces heat. The higher the temperature in the reaction chamber, the less ammonia is produced, as the equilibrium shifts to the right to counteract the heat as it is an exothermic reaction, producing more hydrogen and nitrogen gas. But this doesn’t mean that the rate of reaction will be slower. In general, increasing the temperature always increases the rate of reaction.
b) Pressure. If the pressure of the system is increased, the hydrogen and nitrogen gas molecules are compressed together, and the equilibrium shifts to the right, forming ammonia molecules. Increased pressure also increases the reaction rate, as the gas molecules are more concentrated and closer together.
c) Catalyst. To increase the rate of reaction, a catalyst is used. In the Haber process, the catalyst used is a finely ground porous iron powder, with a large surface area. It absorbs the nitrogen and hydrogen gases and they react with each other on the catalyst’s surface, producing ammonia.
d) Concentration of the reactants. Increasing the concentration of the reactants means the equilibrium shifts to the right producing more ammonia gases. By increasing the concentration of the reactants also means that collisions are suddenly much more frequent for the forward reaction. This increases the forward rate significantly.
e) Removing the product. If the product (ammonia) is removed, causing the equilibrium