Response of Equilibria to Change

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205389184
Posts: 100
Joined: Sat Sep 07, 2019 12:18 am

Response of Equilibria to Change

Postby 205389184 » Sun Jan 12, 2020 9:10 pm

Could somebody explain the quick way to determine a response of equilibria to change? Dr. Lavelle mentioned it in lecture but I hadn't heard of it prior to when he talked about it so I'm still a little confused.

MingdaH 3B
Posts: 133
Joined: Thu Jul 11, 2019 12:17 am

Re: Response of Equilibria to Change

Postby MingdaH 3B » Sun Jan 12, 2020 9:11 pm

The rule of thumb is that the equilibrium will respond in a way that counteracts the change. However, this doesn't give you an accurate representation, so the best way to do so is to recalculate using equations to determine equilibrium.

Gerald Bernal1I
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Re: Response of Equilibria to Change

Postby Gerald Bernal1I » Sun Jan 12, 2020 9:14 pm

With any change the equilibrium will shift a certain way. A general rule is if there is more of reactant, the equilibrium will shift to the right (product) since it has more reactants to form product, and the same goes for an increase of product concentration: it will shift left to create the reactants. For pressure it depends if the volume is being changed or if an inert gas is being added. Change in volume will affect concentration which will follow the rule mentioned above and an inert gas will not affect the system.

Sue Bin Park 2I
Posts: 52
Joined: Mon Jun 17, 2019 7:24 am

Re: Response of Equilibria to Change

Postby Sue Bin Park 2I » Sun Jan 12, 2020 9:16 pm

he was talking mainly about if you are trying to figure out how an equilibrium reacts to a change in pressure.

example equation: A(g) + 2B(g) <-> 2C(g)
if pressure is increased: the equilibrium will shift to produce more of the side that has less overall moles of gas. in our example, it's the right side. this is bc increasing the pressure will incline the system to decrease it in response (le chatelier) and the way to do so is decrease the overall particles of gas that are exerting this "pressure"
if pressure is decreased: the eq will shift to produce the side that has more moles of gas. our left side of the example.

he said this logic isn't quite the whole picture but theres the reasoning we learn in hs chem anyway lol

Sjeffrey_1C
Posts: 108
Joined: Wed Feb 20, 2019 12:17 am

Re: Response of Equilibria to Change

Postby Sjeffrey_1C » Sun Jan 12, 2020 9:18 pm

He basically said that if volume decreases and there are more moles of gas on left, then the reaction shifts left, or if volume decreases and there are more moles of gas on the right, then the reaction shifts left. But this logic is incorrect.

Juliet Stephenson 4E
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Joined: Wed Sep 18, 2019 12:21 am

Re: Response of Equilibria to Change

Postby Juliet Stephenson 4E » Sun Jan 12, 2020 9:22 pm

MingdaH 3B wrote:The rule of thumb is that the equilibrium will respond in a way that counteracts the change. However, this doesn't give you an accurate representation, so the best way to do so is to recalculate using equations to determine equilibrium.


Can you specify which equations we would use to recalculate? Would we just use the pV=nRT

505306205
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Joined: Thu Jul 25, 2019 12:15 am
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Re: Response of Equilibria to Change

Postby 505306205 » Sun Jan 12, 2020 9:29 pm

If stress is put on a system, then the reaction shifts in the direction that minimizes that stress.


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