CHEMISTRY COMMUNITY

What reactions describe when Q=K or is a reaction even present when there is the same amount of product and reactant?

When Q=K, the reaction is at equilibrium, so the forward reaction is occurring at the same rate as the backward reaction.

The reaction is still present and occurring even when the products are equal to the reactants. This just means that P/R ratio is the same so there won't be more products or reactants as the reaction is at equilibrium.

When Q=K, then the reaction is at equilibrium

Pretty much if Q is equal to K that is how you know the equation is at equilibrium.

If Q=K, as everybody has been saying, you know the equation has reached its equilibrium. However, K really is the right way to label the ratio of reactants to products at equilibrium.

If Q = K, then the reaction is at equilibrium.

When Q=K the reaction is at equilibrium meaning that the forward and reverse reactions are happening at the same rate. This does not mean that they are not occurring, but rather [R] and [P] are being formed at the same time, and neither is being formed more than the other.