Equilibrium Constant vs Reaction Quotient [ENDORSED]

[Ronica_Patel_3G]

Since you calculate the reaction quotient Q and the equilibrium constant K using the same method, how will you be able to compare the two values to determine the direction it will go? Wouldn't they be the same value?

[Sangita_Sub_3H]

Hi! Although Q and K are calculated the same way, the same numbers are not used. For Q, the numbers that are used for the calculation are not at equilibrium; rather, they are measured values at a specific point in time. However, when measuring K, the values used are at equilibrium, which is why Q and K are comparable.

Hope this helps!

[nick_pantoja_3G]

And with those Q and K values, you will be able to compare and see which side is favored.

[Marisa_Woo_2G]

Just to clarify, the values used to calculate K and Q should be concentrations? Would this refer to molar concentrations like moles/liter and molarity for aqueous solutions? And then partial pressure for concentrations of gas?

[Julia Nakamura 2D]

Yes. So when calculating Q and K, either pressures (for gases) or concentrations in moles/L (molarity for aqueous solutions) are used. Q and K do not have units, but the values used to solve for Q and K will have units.