Pressure and volume


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Deepika Pugalenthi 1A
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Joined: Fri Sep 28, 2018 12:24 am

Pressure and volume

Postby Deepika Pugalenthi 1A » Fri Jan 11, 2019 12:19 pm

Are pressure and volume inversely related when identifying the direction a reaction is going to go when changing either factor? For example, if I want to increase the pressure, the reaction would move to the side with fewer moles and vice versa?

Tarika Gujral 1K
Posts: 62
Joined: Fri Sep 28, 2018 12:27 am

Re: Pressure and volume

Postby Tarika Gujral 1K » Fri Jan 11, 2019 12:24 pm

Pressure and volume are inversely related, according to Boyle’s law.

Thus increasing pressure implies a decrease in volume.
Decreasing volume causes reaction to move to side with fewer moles of gas.
So increasing pressure causes reaction to move to side with fewer moles of gas.

Faith Fredlund 1H
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Joined: Fri Sep 28, 2018 12:18 am

Re: Pressure and volume

Postby Faith Fredlund 1H » Fri Jan 11, 2019 2:49 pm

PV=nRT where P= pressure, V=volume, n= moles, R= gas constant, T=temperature, shows that pressure and volume do indeed have an inverse relationship. Assuming moles, the gas constant, and the temperature do not change (let's call their collective product 1 for simplicity), you now get the equation PV=1 or P=1/V. This shows that they do indeed have an inverse relationship.

michelle
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Joined: Fri Sep 28, 2018 12:23 am

Re: Pressure and volume

Postby michelle » Fri Jan 11, 2019 4:46 pm

Not always. For instance, when the pressure is increased by adding inert gas and the container is not changed, the volume stays the same.

Riley Dean 2D
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Joined: Fri Sep 28, 2018 12:15 am

Re: Pressure and volume

Postby Riley Dean 2D » Sat Jan 12, 2019 11:06 pm

If the pressure is increased by decreasing volume then that is correct but if pressure is increased by pumping gas in then that would be incorrect because moles and volume will have stayed constant and therefore the concentrations will have stayed constant and no change in the reaction will occur


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