Le Chatelier's Principle question

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

Le Chatelier's Principle question

Postby chloewinnett1L » Fri Jan 25, 2019 1:32 am

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
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Re: Le Chatelier's Principle question

Postby Michael Torres 4I » Fri Jan 25, 2019 7:55 am

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
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Re: Le Chatelier's Principle question

Postby Ray Huang 1G » Fri Jan 25, 2019 8:54 am

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
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Re: Le Chatelier's Principle question

Postby Elle_Mendelson_2K » Fri Jan 25, 2019 11:00 am

How does expansion and compression effect the reaction?

uhedlund
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Re: Le Chatelier's Principle question

Postby uhedlund » Sun Jan 27, 2019 8:33 pm

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.


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