CHEMISTRY COMMUNITY

What’s the difference between them seeing as they’re calculated the same way?

Q is when the reaction is not at equilibrium, K is when the reaction is at equilibrium. If Q<K, the reaction shifts right to favor the products. If Q>K the reaction shifts left to favor the reactants. Most of the time it is Q that changes, not K. K is changed by temperature only.

Q is used to compare to K when at equilibrium. It tells us which way the non-equilbrium solution will shift in order to reach equilibrium. When this state is reached, Q = K.

Q is called the "reaction quotient," and can be calculated anytime during the reaction. K is called the "equilibrium constant", and can be calculated only when the reaction has reached equilibrium. For a specific reaction (at a constant temperature and pressure), you can get different Q values depending on when during the reaction you calculate it and the initial concentrations of reactants/products, but you will only get one K value.

Q is calculated with values that are at any point in the reaction. We can use our answer from Q and compare to to the constant K value to determine whether the reaction will proceed forward or reverse.

As the Q and K value approach each other, does the rate at which products and reactants are converted ever decline or is the reaction a constant rate?

As Q approaches K, the rate of the forward or reverse reaction might change so that the rates of the forward and reverse reactions are equal.

K is the constant at equilibrium while Q is approaching the equilibrium. Solving for Q and comparing it to the K constant can get you the direction in which the reaction is favoring.

Since K is only for when it's at equilibrium, the value is only K IF it's at equilibrium. When it's not at equilibrium, it is Q.

Q doesn't mean anything until it is compared to K. The comparison helps to determine which direction the reaction will proceed given time.

Q is when the reaction is not at equilibrium. K is when the reaction is at equilibrium. Q is compared to K to determine whether the reaction will shift to the left or right due to the Le Chatalier's Principle.

Q can be calculated at any point in the reaction, whereas K is only calculated at equilibrium

Q is the concentrations of the products over the reactants when the equation is not at equilibrium; K is the concentration of the products over the reactants when the equation is at equilibrium.

Q is not always at equilibrium but it can be; it is most often used to show to which side the reaction will shift to