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### Not including solids and liquids

Posted: Sun Jan 19, 2020 8:14 pm
Are solids and liquids always negated in calculations dealing with equilibrium constants? And if so, why?

### Re: Not including solids and liquids

Posted: Sun Jan 19, 2020 8:17 pm
Solids and liquids are not used in calculating an equilibrium constant, only gasses and aqueous solutions are considered. This is because the activity of the pure solids and liquids are considered to be 1, so it would not affect the equilibrium equation (their concentrations do not change throughout the experiment).

### Re: Not including solids and liquids

Posted: Sun Jan 19, 2020 8:28 pm
The activity of a pure solid or liquid is equal to 1 so it doesn't affect the value of the equilibrium constant.

### Re: Not including solids and liquids

Posted: Sun Jan 19, 2020 8:41 pm
K is calculated with the concentration of the products over the concentration of the reactants at equilibrium. Since solids and liquids in a reaction do not change concentrations, they would just cancel out when calculating the equilibrium constant. So, only gases are considered when calculating K.

### Re: Not including solids and liquids

Posted: Sun Jan 19, 2020 8:51 pm
Solids and liquids are not included in the equilibrium constant equation because they do not have concentrations. They have densities. Therefore, they are negated when calculating the K value.

### Re: Not including solids and liquids

Posted: Sun Jan 19, 2020 8:53 pm
Pure liquids and solids have an activity level of 1, and thus do not need to be included in equilibrium equations.

### Re: Not including solids and liquids

Posted: Sun Jan 19, 2020 9:17 pm
Solids and liquids do not affect the equilibrium in any significant way, and are not measured in concentrations; as a result, they are left out in K value calculations.

### Re: Not including solids and liquids

Posted: Sun Jan 19, 2020 9:55 pm
Solids and liquids equal 1 so they are neglected when calculating K.