Reaction Quotient


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TiffanyL1G
Posts: 49
Joined: Thu Sep 27, 2018 11:22 pm

Reaction Quotient

Postby TiffanyL1G » Thu Jan 10, 2019 3:32 pm

Why is it that when solving for Q, the reaction quotient, we disregard the solids and the liquids in the chemical equation? I think we disregard solids because it isn’t possible to find the concentration of a solid but why do we disregard liquids?

Noah Fox 1E
Posts: 15
Joined: Thu Sep 27, 2018 11:20 pm

Re: Reaction Quotient

Postby Noah Fox 1E » Thu Jan 10, 2019 3:38 pm

Because they do not affect the concentrations of reactants and products, liquids are not taken into account for equilibrium reactions. That being said H2O undergoes a acid base reaction with itself when it produces hydrogen ions and hydroxide ions spontaneously, but it goes disregarded because water naturally stabilizes at 7 ph.

RachelCheung1A
Posts: 18
Joined: Thu Sep 27, 2018 11:19 pm

Re: Reaction Quotient

Postby RachelCheung1A » Thu Jan 10, 2019 4:22 pm

We disregard solids and liquids because their concentrations are the same throughout the reaction. Concentration equals to density divided by molar mass and both solids and liquids' densities are pretty much constant, therefore concentrations of solids and liquids are constant.

Aili Ye 4L
Posts: 46
Joined: Thu Sep 27, 2018 11:16 pm

Re: Reaction Quotient

Postby Aili Ye 4L » Fri Jan 11, 2019 3:05 pm

We don't include liquids and solids because by convention the values in the K expression change over time, and the concentration of liquids and solids do not change.

fgalasso1b
Posts: 13
Joined: Tue Oct 02, 2018 11:15 pm

Re: Reaction Quotient

Postby fgalasso1b » Fri Jan 11, 2019 3:33 pm

Both solids and liquids are pure so they don't have a concentration. Having no concentration means they are not included in the calculations of K or Q.

fgalasso1b
Posts: 13
Joined: Tue Oct 02, 2018 11:15 pm

Re: Reaction Quotient

Postby fgalasso1b » Fri Jan 11, 2019 3:34 pm

Both solids and liquids are pure so they don't have a concentration. Having no concentration means they are not included in the calculations of K or Q.

Charles Gu 1D
Posts: 48
Joined: Thu Sep 27, 2018 11:16 pm

Re: Reaction Quotient

Postby Charles Gu 1D » Thu Jan 17, 2019 5:53 pm

Since solids and liquids concentrations will not change, they will be eventually canceled out. Therefore, they are not included.


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