Pressure changes

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Clarice Chui 2C
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Joined: Fri Aug 30, 2019 12:16 am

Pressure changes

Postby Clarice Chui 2C » Mon Jan 20, 2020 12:33 am

Let's say that the partial pressure of a reactant was increased. How do you use Le Chatelier's principle/reasoning to predict and understand what happens?

Naneeta Desar 1K
Posts: 106
Joined: Fri Aug 09, 2019 12:15 am

Re: Pressure changes

Postby Naneeta Desar 1K » Mon Jan 20, 2020 12:40 am

If the pressure is increased then the reaction will favor the side where there are less moles of either the products or the reactants.

Sanjana K - 2F
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Re: Pressure changes

Postby Sanjana K - 2F » Mon Jan 20, 2020 3:11 am

The easy way to tell what changes will occur is to see how the moles of gas on the reactants and products sides differ. If the volume (moles of gas) is lower on the products side, then the reaction shifts to the right but if the volume (moles of gas) is higher on the products side, the reaction shifts left. Essentially changes in pressure indicate changes in volume, which indicates changes in concentration so the reaction shifts directions. But K won't change because the temperature is still the same.

Jessica Chen 2C
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Joined: Thu Jul 11, 2019 12:17 am

Re: Pressure changes

Postby Jessica Chen 2C » Mon Jan 20, 2020 11:29 am

When it comes to the partial pressure of a reactant/product changing, you can basically think of it as a change in concentration. So if the partial pressure of a reactant increased, then the reaction would shift to the right/to the products. But if they're talking about the pressure of the reaction overall, that's when you consider the moles of gas to determine what will happen.

Ashley Alvarado 2C
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Joined: Sat Aug 17, 2019 12:16 am

Re: Pressure changes

Postby Ashley Alvarado 2C » Mon Jan 20, 2020 10:25 pm

If the partial pressure of a reactant was increased, the volume will decrease and there will be more moles of gas on the right, so the reaction shifts left.

Sam McNeill 1E
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Joined: Sat Aug 24, 2019 12:17 am

Re: Pressure changes

Postby Sam McNeill 1E » Tue Jan 21, 2020 10:21 am

Look at which side is affected more in terms of the exponents when you solve for a new Q. When volume is halved, concentration doubles and then apply the exponents to that double to find if Q is greater then or less than K, then decide which direction the reaction will proceed in.

Kaylee Clarke 1G
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Joined: Fri Aug 30, 2019 12:15 am

Re: Pressure changes

Postby Kaylee Clarke 1G » Tue Jan 21, 2020 11:37 am

I think of it like this. You want the products and reactants to be equal, hence equilibrium. So, if one side increases, the reaction shifts to the other side so that it may find equilibrium again.

AniP_2D
Posts: 95
Joined: Sat Aug 17, 2019 12:17 am

Re: Pressure changes

Postby AniP_2D » Wed Jan 22, 2020 4:16 pm

If the pressure is increased, the system shifts to the side with less moles, and if the pressure is decreased, the system shifts to the side with more moles.


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