ignoring solids

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FrankieClarke2C
Posts: 59
Joined: Fri Sep 28, 2018 12:28 am

ignoring solids

Postby FrankieClarke2C » Fri Jan 18, 2019 5:06 pm

Why do we ignore liquids calculating Q? I was doing problem 11.13 and was confused how they got that answer for part a

Shivangi_2J
Posts: 65
Joined: Fri Sep 28, 2018 12:15 am

Re: ignoring solids

Postby Shivangi_2J » Fri Jan 18, 2019 5:19 pm

The concentration of solids and liquids essentially remains constant throughout the reaction so we don't include them in K or Q expressions.

Nandhini_2K
Posts: 60
Joined: Fri Apr 06, 2018 11:03 am

Re: ignoring solids

Postby Nandhini_2K » Fri Jan 18, 2019 7:46 pm

Solids and Liquids don't affect the reactant amount at equilibrium, so we leave them out.

Rami_Z_AbuQubo_2K
Posts: 89
Joined: Thu Jun 07, 2018 3:00 am

Re: ignoring solids

Postby Rami_Z_AbuQubo_2K » Sat Jan 19, 2019 12:43 am

You ignore pure liquids because only a small amount ends up reacting, meaning the amount in the products and reactants are practically the same and cancel out when you put the liquid in both the denominator and numerator of the equilibrium ratio. As for solids, there is no such thing as a concentration of a solid.

LeannaPhan14BDis1D
Posts: 57
Joined: Fri Sep 28, 2018 12:16 am

Re: ignoring solids

Postby LeannaPhan14BDis1D » Sat Jan 19, 2019 6:48 pm

In the endgame result for K or Q solids and pure liquids will not affect the results.

Nicholas Le 4H
Posts: 74
Joined: Fri Sep 28, 2018 12:24 am

Re: ignoring solids

Postby Nicholas Le 4H » Sat Jan 19, 2019 9:07 pm

We leave out solids and liquids because they do not affect the equilibrium. We only account for species in the aqueous and gas phases when calculating equilibrium.

Angela Cong 3C
Posts: 69
Joined: Fri Sep 28, 2018 12:25 am

Re: ignoring solids

Postby Angela Cong 3C » Sat Jan 19, 2019 9:35 pm

The change in liquids such as water is so small in even in equilibrium there is large excess of it so it would cancel out in K and thus is not included. Solids also don’t affect the constant and is left out as well


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