For the general, single-step reaction A1g2 + B1g2 ∆ AB1g2, Kc = 4.5 * 10-6, which of the following statements is true? (LO 15.16) (a) Ea 1forward2 6 Ea 1reverse2 (b) The equilibrium mixture contains mostly products. (c) kr 7 kf (d) The reaction is exothermic.

Video transcript

Hello. In this problem we are told the equilibrium constant for the single step reaction X plus Y. Goes to X. Y. Is three times 10 3 were asked which of the following is true. Let's begin by writing the equilibrium constant expression. So it's our product concentration. The one power divided by our reactant concentrations. Also to the one power we're told this is equal to three times 10 to the three. Recall that if we have an equilibrium constant that is much larger than one reaction favors products. And right, this makes sense given that our products are in the numerator. So if the equilibrium constant is large it means our product concentrations are large and if our equilibrium constant is much less than one then the reaction favors reactant. And this makes sense. Right? Our reactant sar in the denominator. So if this is large then our equilibrium constant will be small. And if we have An equilibrium constant that is close to one reaction favors neither react into products. We have that equal amounts will reach equilibrium. So in this case our equilibrium constant is greater than one. So this would indicate that it favors product formation. We call also that okay reverse is equal to one over K forward. So the equilibrium constant for the reverse reaction will be 1/3 times 10 to the three, Which would be equal to 3.3 times 10 to the -4. So that means that are okay forward is greater than R. K. Reverse. So when we look at the answers that were given the first one says that the reaction is eggs are thermic, so we cannot determine whether the ex reaction is exo thermic or endo thermic based on the equilibrium constant. The next one says the reaction. The reverse reaction is favored, so K reverse is greater than K forward, so that's not true Right? We found that the forward reaction is favored because our equilibrium constant is greater than one and that R K forward equilibrium constant is greater than that for the reverse. So the correct answer is the thanks for watching. Hope this helps.