solids on the reactant side

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madisondesilva1c
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Joined: Fri Sep 28, 2018 12:16 am

solids on the reactant side

Postby madisondesilva1c » Mon Jan 14, 2019 12:13 pm

If there is a solid for a reactant, do you assume that the solid is added to a flask containing water, therefore it really is in aqueous form. Dr. Lavelle mentioned in lecture that you assume the water is present, but are there any cases where assuming water is present incorrect and could lead you to computing an incorrect equilibrium constant?

Fayez Kanj
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Re: solids on the reactant side

Postby Fayez Kanj » Mon Jan 14, 2019 12:40 pm

Hello

Yes, assume that the solid is added to a beaker/flask/test tube of water. You can also imaging having a +H2O on both the reactant and product side. In either way, solids and liquids (water) are never included in the calculation of the equilibrium constant, so should have no impact on your final answer for K.

Hope this helps :)

Chem_Mod
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Re: solids on the reactant side

Postby Chem_Mod » Mon Jan 14, 2019 1:16 pm

If a reactant or product is written as X(aq), it is dissolved in water, and water is present, even if not directly involved in the reaction. If it is listed as X(s), do not assume there is water unless it is explicitly written as a reactant or product or another reactant or product is aqueous. The water or X(s) are not included in the equilibrium constant (or more accurately, they are included with an activity of 1).

Kayla Vo 1B
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Joined: Fri Sep 28, 2018 12:26 am

Re: solids on the reactant side

Postby Kayla Vo 1B » Mon Jan 14, 2019 2:28 pm

Solvents and solids are not included when calculating the equilibrium constant K, so they dont change the value of the equilibrium constant. If a compound is stated to be aqueous, you can assume there is water. However, you can not assume there is water if there is only a solid compound stated and no other aqueous reactants.


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