Solids and Liquids

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Solids and Liquids

Postby 805383532 » Sun Jan 19, 2020 11:21 am

Why are solids and liquids disregarded when calculating K and Q?

Kimberly Koo 2I
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Re: Solids and Liquids

Postby Kimberly Koo 2I » Sun Jan 19, 2020 12:00 pm

The change in solvent concentration is insignificant, which is why pure liquids are eliminated from the equilibrium expression.

William Chan 1D
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Re: Solids and Liquids

Postby William Chan 1D » Sun Jan 19, 2020 12:20 pm

Solids and liquids are essentially non-compressible, so their concentrations don't really change. Gas concentrations or ion concentrations will change though, those are the values we calculate for.

Matt F
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Joined: Sat Aug 17, 2019 12:17 am

Re: Solids and Liquids

Postby Matt F » Sun Jan 19, 2020 3:19 pm

Most solids and liquids are pure substances, meaning their molar concentration does not change in the reaction. Therefore, it will not affect the equilibrium concentrations of other reactants/products

Viviana Velasquez
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Joined: Sat Jul 20, 2019 12:15 am

Re: Solids and Liquids

Postby Viviana Velasquez » Sun Jan 19, 2020 6:42 pm

Lavelle mentioned that it had something to do with their concentrations not changing so they were insignificant.

Chris Charton 1B
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Joined: Mon Jun 17, 2019 7:23 am

Re: Solids and Liquids

Postby Chris Charton 1B » Sun Jan 19, 2020 7:38 pm

Pure solids and liquids do not affect reactant amounts in the equation so they are not included in the equation. If you included them they would have an activity level of 1, thus not changing the equation.

Posts: 104
Joined: Fri Aug 30, 2019 12:17 am

Re: Solids and Liquids

Postby RobertXu_2J » Sun Jan 19, 2020 8:04 pm

Because changes to their concentration are inconsequential for the rate of reaction. Solids just sit there, they don't really have a concentration because they don't mix with the solvent. Liquids are the solvent, so you assume that there will always be enough of it that any decrease will be insignificant for the rate of reaction.

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