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Topic: Equilibrium Question  (Read 4470 times)

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Offline positiveion

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Equilibrium Question
« on: August 21, 2010, 03:38:12 AM »

Offline Borek

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Re: Equilibrium Question
« Reply #1 on: August 21, 2010, 04:50:44 AM »
Concentration of water is assumed to be constant, so it is moved into Keq value.
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Offline sjb

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Re: Equilibrium Question
« Reply #2 on: August 21, 2010, 04:54:29 AM »
BF3 (aq) + 3 H2O (aq)  ::equil:: 3 HF(aq) + H3BO3 (aq)

Keq = [HF]3 x [H3BO3] / [BF3]

(please consider typing questions out, it makes the search function more efficient)

The main reason that water is not considered in this instance is because it's the solvent, any changes in its concentration as a result of the reaction will be very small, effectively a constant in this case. If the reaction were much more concentrated then it would probably be best to include it as well.

Offline dkasprick

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Re: Equilibrium Question
« Reply #3 on: August 25, 2010, 04:35:57 AM »
Isnt it because pure solids and pure liquids arent included in equilibrium  constant expressions ?

Offline Borek

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Re: Equilibrium Question
« Reply #4 on: August 25, 2010, 06:18:59 AM »
No, that holds when they are in separate phases.
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