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### K

Posted: Thu Jan 10, 2019 9:37 am
What is the difference between K[p], K[eq], and K[p]? When do you use each and what are the units?

### Re: K

Posted: Thu Jan 10, 2019 10:52 am
Kp is for pressure, Kc is molarity and I guess Keq is just in equilibrium.

### Re: K

Posted: Thu Jan 10, 2019 10:56 am
K(p) is the equilibrium constant in terms of partial pressure. This constant is used when all products and reactants in a reaction are in the gas phase. I'm not sure what K(eq) but I'm guessing you might be referring just to K, which is used for reactions with products and reactants that aren't all in the gas phase, using molarity. Neither of these two K's have units, as the units in the numerator and denominator of the fraction used to calculate K are the same, and therefore cancel out.

### Re: K

Posted: Thu Jan 10, 2019 11:03 am
Kp= partial pressure Equilibrium constant; used when it is in the gas phase
Kc= molar concentration equilibrium constant; used in concentrations other than gas since gases do not have concentrations
Keq= typically written to write an equilibrium expression

The units of Keq are "dimessioness" or in other words have NO units.

### Re: K

Posted: Thu Jan 10, 2019 11:08 am
I believe each K (other than Keq) has units but when it is placed into the equation the units are no longer needed.