Consider the dissociation reaction A₂(g) ⇌ 2 A(g). The following pictures represent two possible initial states and the equilibrium state of the system:

(b) What are the signs ( + , - , or 0) of ∆H, ∆S, and ∆G when the system goes from initial state 1 to the equilibrium state? Explain. Is this a spontaneous process?

Video transcript

Hello everyone today. We have the following problem. The following figures illustrate the initial state and the equilibrium state of the reaction. As follows, determine whether the reaction is spontaneous or non spontaneous. What are the signs of the change in entropy? The change in entropy and our change in Gibbs free energy when the reaction proceeds from its initial state to the equilibrium state. So to first determine the sign of our change in our in philippi we must take into account that the reaction is endo thermic since it is involving the breaking of bonds. Therefore our change in entropy is going to be greater than zero because we are requiring energy. Next we can examine the change in our entropy. So we see here that the equilibrium state has more molecules in the initial state which is going to result in an increase in the disorder overall of the system. Therefore this is going to make our change in entropy greater than zero. Next we can set up our Gibbs free energy equation to figure out what our delta G. Was going to be. So we have our change in entropy is equal to the change our gives her injury is equal to the change in entropy minus temperature times our change in entropy. So since the reaction is endo thermic, it's more likely to occur at higher temperatures. And so since our change in info P and entropy are positive, this temperature is going to be a negative sign and therefore it's going to make our gibbs free energy less than zero. So if our Gibbs free energy is less than zero, this reaction is going to be spontaneous. So our overall signs are going to be positive for our change in entropy, positive for a change in entropy and negative for our gives free energy. And so this is going to be our final answers. And with that, I hope this helped, and until next time.