Reaction Quotient Q

[Neha Thakkar 2H]

Is q her when only pure solids and liquids are present in the equation? Or would it be 1?

[Pam Nelson 1B]

For q, we don't include solids and liquids in the equation, just like for k. We use q when the reaction is not at equilibrium. Then the value of q, in comparison to k, helps us determine in which direction the reaction will proceed. For example if Q<K, then product formation is favored and the reaction will shift right.

[joselle barnoya 1k]

The reactant quotient tells us the progress of a reaction. When Q = 0 this indicates that the concentration of reactants is non-zero and that no products have been formed. Recall that 0 divided by any number is 0, however, 0 divided by 0 is undefined. This tells us that there is some amount of reactants which, if our reaction consisted of only pure liquids and solids, would not be the case (none of the reactants would be considered in calculating Q in that case as the concentration of pure solids and liquids does not change throughout the course of the reaction).