Final answer:
Removing heat from an endothermic reaction will cause the equilibrium to shift toward the reactants, resulting in a decrease in the concentration of carbon monoxide.
Step-by-step explanation:
For the endothermic reaction being discussed, removing heat from the system would cause a shift in the equilibrium to absorb more heat, according to Le Chatelier's Principle. This means the reaction will shift toward the reactants to absorb the heat that was removed. Therefore, when heat is removed from the endothermic reaction, the concentration of carbon monoxide (CO) will decrease as the reaction shifts to the left, producing more reactants.