Question 15.55 (Sixth Edition)

[Steve Magana 2I]

Question: Indicate whether each of the following statements is true or false. If a statement is false, explain why. (a) For a reaction with a very large equilibrium constant, the rate constant of the forward reaction is much larger than the rate constant of the reverse reaction. (b) At equilibrium, the rate constants of the forward and reverse reactions are equal. (c) Increasing the concentration of a reactant increases the rate of a reaction by increasing the rate constant in the forward direction.

Can someone help me with these questions please, I always have trouble with the conceptual parts. Thank you!

[timothy_ho_4B]

a is true because the equilibrium constant K is equal to k/k' which is the forward rate constant divided by the reverse rate constant. So if K is very large, that implies that k is much larger than k', showing that the forward rate constant is much larger than the reverse rate constant.

b is false because at equilibrium, the RATES are equal, but the rate constants can be very different. If the rate constants were equal, then all equilibrium constants would be 1 at equilibrium, which doesn't make sense.

c is false because even though increase the reactant concentration increases the rate of a reaction, increasing the reactant concentration does not affect the rate constant itself. The rate constant does not change based on concentration of reactants, but can be changed by temperature, activation energy, and rate of collisions.