Determine the effect of temperature change on chemical systems at equilibrium by considering the enthalpy change for the forward and reverse reactions.

The reaction $\text{PCl}_5(g) \rightleftharpoons \text{PCl}_3(g) + \text{Cl}_2(g)$ is endothermic in the forward direction. If the temperature of the system at equilibrium is decreased, which change will occur?

The equilibrium system shown below is initially at equilibrium at 400 K. $$\ce{C2H4(g) + H2(g) <=> C2H6(g)} \quad \Delta H = -137 \text{ kJ/mol}$$ The temperature is then increased to 550 K. Which statement correctly describes the effect of this temperature increase on the equilibrium system?

The decomposition of dinitrogen tetroxide is represented by the equilibrium equation: $$\text{N}_2\text{O}_4(g) \rightleftharpoons 2\text{NO}_2(g) - 58 \text{ kJ mol}^{-1}$$ Determine whether increasing the temperature of this system will shift the equilibrium towards the reactants or products. Justify your answer by considering the enthalpy change of the forward reaction.