Dissociation of a diatomic molecule, X2(g)<-->2 X(g) occurs at 500 K. The equilibrium state of the reaction is shown in 1 and the equilibrium state in the same container after a change has occurred is shown in 2. Which of the following changes will produce the composition shown? (a) Increasing the tempera- ture. (b) Adding X atoms. (c) Decreasing the volume. (d) Adding a catalyst. Explain your selections.
(container 1 shows 8 X2 molecules and 6 X molecules. container 2 shows 2 X2 molecules and 18 X molecules)
The answer is a, with the reasoning being that the reaction is endothermic. Why is the reaction endothermic? I thought breaking bonds released energy.