American Chemical Society (ACS) Chemistry Practice Exam 2025 - Free ACS Chemistry Practice Questions and Study Guide

In the given equilibrium reaction, heat is a part of the system, indicating that this is an endothermic reaction, which means that it absorbs heat as it proceeds towards the products.

When the equilibrium is disturbed, the system will react in a way that attempts to counteract that disturbance according to Le Chatelier's principle. Increasing the reaction temperature provides additional heat, which will shift the equilibrium towards the right side (the products), favoring the formation of CaO and SO2. Since the right side of the reaction produces more moles of gas than the left side, this shift will lead to an increase in pressure when the equilibrium is reestablished.

In contrast, removing SO2 would shift the equilibrium to the left to produce more SO2, therefore not increasing the pressure. Decreasing the temperature would favor the reactants in an endothermic reaction, moving the equilibrium in the opposite direction and further reducing pressure. Decreasing the reaction volume would also increase pressure, but it would have a different specific effect based on the mole distribution on each side of the reaction. Since this question asks for an increase in pressure specifically due to temperature changes, providing heat or increasing the temperature directly promotes the production of gas molecules and thus increases the pressure.