Reducing Volume

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Nathan Mariano 2G
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Joined: Fri Sep 28, 2018 12:29 am

Reducing Volume

Postby Nathan Mariano 2G » Mon Jan 14, 2019 1:05 am

What is the effect of adding an inert gas to a system at equilibrium compared to using a piston to reduce the volume of the gases at equilibrium?

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Joined: Fri Sep 28, 2018 12:24 am

Re: Reducing Volume

Postby kateminden » Mon Jan 14, 2019 1:55 am

I am confused about this too! I still do not understand why the change in pressure created when an inert gas is added to a closed system at equilibrium does not affect the equilibrium.

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Joined: Fri Sep 28, 2018 12:27 am

Re: Reducing Volume

Postby Katie_Duong_1D » Mon Jan 14, 2019 4:57 am

Adding an inert gas has no effect because the partial pressures remain the same, so the system is still at equilibrium. If you reduce volume, that increases pressure according to the ideal gas law, PV = nRT. To determine whether the system shifts left or right, first determine whether there are more moles on the left or right. If the moles are equal, there is no effect to reducing volume. If there are more moles on the right, then a decrease in volume would shift right and an increase in volume would shift left.

Sophia Ding 1B
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Joined: Fri Sep 28, 2018 12:16 am

Re: Reducing Volume

Postby Sophia Ding 1B » Wed Jan 16, 2019 4:17 pm

It's easier to think in terms of concentration; although the pressure of the vessel will definitely change with the addition of the inert gas, the inert gas has no real effect to the system equation itself. This is because this inert gas will not change the concentration (or partial pressure) of neither the reactants nor products, thus not shifting the system out of equilibrium despite changing the overall volume and pressure of the reaction vessel itself.

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