Decreasing pressure

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eduardomorales5
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Joined: Fri Aug 30, 2019 12:15 am

Decreasing pressure

Postby eduardomorales5 » Tue Feb 11, 2020 10:42 pm

Why does decreasing pressure cause the reaction to shift toward the side that has more moles?

Victoria Zheng--2F
Posts: 103
Joined: Fri Aug 09, 2019 12:17 am

Re: Decreasing pressure

Postby Victoria Zheng--2F » Tue Feb 11, 2020 10:49 pm

Because when you decrease the pressure, the volume increases, which means that the molar concentrations of the reactants and products decrease. Since the molar concentrations of gases and aqueous solutions are inversely related to volume, increasing the volume decreases the molar concentration of the gases and aqueous solutions. The side with more moles of gas and aqueous solutions will experience a greater decrease, which will shift the equilibrium toward the side towards it.

CameronDis2K
Posts: 51
Joined: Wed Feb 20, 2019 12:18 am

Re: Decreasing pressure

Postby CameronDis2K » Wed Feb 12, 2020 1:38 pm

A decrease in pressure corresponds to a higher volume (as pressure and volume are inversely proportional according to the ideal gas law, PV=nRT). So the reaction side with more moles of GAS is favored, as the higher moles of gas can occupy the larger value to return the reaction to equilibrium.

Natalie Benitez 1E
Posts: 100
Joined: Fri Aug 02, 2019 12:15 am

Re: Decreasing pressure

Postby Natalie Benitez 1E » Mon Feb 17, 2020 1:55 pm

In retrospect by decreasing pressure you are increasing volume since P and V are inversely related to each other. By increasing the volume you essentially have more space for gas to move about, therefore, favoring the side with more moles of gas.

Brian J Cheng 1I
Posts: 115
Joined: Thu Jul 11, 2019 12:15 am

Re: Decreasing pressure

Postby Brian J Cheng 1I » Mon Feb 17, 2020 4:24 pm

To summarize, you can think of this in two ways: thinking about it in terms of concentration as Victoria Zheng--2F explained above, or the quicker way of gases occupying areas naturally as CameronDis2K and Natalie Benitez 1E have said. Whatever floats your boat!

005321227
Posts: 90
Joined: Sat Sep 07, 2019 12:15 am

Re: Decreasing pressure

Postby 005321227 » Wed Feb 19, 2020 1:31 am

a decrease in pressure means an increase in volume.

Justin Sarquiz 2F
Posts: 106
Joined: Fri Aug 30, 2019 12:15 am

Re: Decreasing pressure

Postby Justin Sarquiz 2F » Wed Feb 19, 2020 8:37 am

We did an example in class with actual numbers to show how decreasing the volume, increased concentration (n/V) and made equilibrium shift to the side with fewer gas moles. You can use the same numbers to show how increasing the volume makes equilibrium shift to the side with more gas moles.

Mai V 4L
Posts: 111
Joined: Fri Sep 28, 2018 12:23 am

Re: Decreasing pressure

Postby Mai V 4L » Mon Mar 09, 2020 2:33 pm

an someone please give me a quick rundown on this or send a link to a resource? Thanks


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