## Le Chatelier's Principle question

chloewinnett1L
Posts: 55
Joined: Fri Sep 28, 2018 12:20 am

### Le Chatelier's Principle question

What is the difference between changing pressure by adding an inert gas and changing pressure by decreasing volume when you are trying to use Le Chatelier's principle to calculate reaction dynamics? Why?

Michael Torres 4I
Posts: 92
Joined: Thu May 10, 2018 3:00 am
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### Re: Le Chatelier's Principle question

Changing pressure by adding inert gas does not affect the reaction. It may slow down the reaction's rate somewhat, but it will not affect the equilibrium constant or the reaction quotient.

On the other hand, changing pressure by altering volume does alter the reaction quotient. Concentration in terms of molarity depends directly on the value of the volume.

Molarity=moles/liters

Because altering volume affects concentration, then altering pressure through a change in volume will have a direct effect on the reaction. The reaction will then attempt to reach equilibrium again after undergoing this perturbation, and as such either the products or reactants might become favored.

Ray Huang 1G
Posts: 30
Joined: Fri Sep 28, 2018 12:20 am

### Re: Le Chatelier's Principle question

The reason pressure affects the reaction is the probability of one molecule colliding into another. The collision is what results in a change. If you increase the pressure by adding an inert gas, the molecule in question for the reaction crashing into the inert gas won't result in a reaction. The molecule must hit something it can react with.

Elle_Mendelson_2K
Posts: 72
Joined: Fri Sep 28, 2018 12:28 am

### Re: Le Chatelier's Principle question

How does expansion and compression effect the reaction?

uhedlund
Posts: 38
Joined: Wed Nov 15, 2017 3:03 am

### Re: Le Chatelier's Principle question

Expansion will result in an increase in volume and therefore a decrease in pressure. The reaction will likely then favor the side of the reaction that has been expanded since its pressure is lower. Compression will result in a decrease in volume and an increase in pressure. Therefore, the reaction will favor the side of the reaction that has not been compressed.