## effect on equilibrium by changing volume

505166714
Posts: 50
Joined: Fri Sep 28, 2018 12:17 am

### effect on equilibrium by changing volume

How do I explain the change in equilibrium with reaction quotient (Q) after changing the volume?

Jake Gordon 1A
Posts: 61
Joined: Fri Sep 28, 2018 12:15 am

### Re: effect on equilibrium by changing volume

Well, it depends how the volume has been changed. Lets say that the volume is halved, this doubles pressure because they are inversely related.
for N2+ 3H2 ==> 2NH3
If the partial pressures at equilibrium are all .1, the K value is 100

When the volume halves, the concentration doubles because C=number of moles divided by volume. if n is constant and V decreases, C increases. The new concentrations are now .2, now we would be calculating Q because it is not at equilibrium
Q would equal 25 which is less than K meaning that the forward reaction is favored (there are currently many reactants)

JacobHershenhouse3G
Posts: 32
Joined: Thu Jan 10, 2019 12:17 am

### Re: effect on equilibrium by changing volume

Remember that Q is the constant at any given point in time and has applications that dont involve the changing of equilibrium concentrations. The important thing to note is that BOTH K and Q change when you alter volume or temperature (to reflect the change in equilibrium concentration values). So, if you want to express that equilibrium has changed, demonstrate that there is a new K, not a new Q. Hope this helps!

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