If the temperature of the system PCl5 (g) =PCl3 (s) + Cl2 (g) + 92.5 kj. is increased, predict the direction of th Le Chatelier's shift.
To predict the direction of the Le Chatelier's shift when the temperature of the system PCl5 (g) = PCl3 (s) + Cl2 (g) + 92.5 kJ is increased, we need to consider the effect of temperature on the equilibrium.
The balanced equation indicates that the reaction is exothermic, as it releases energy (92.5 kJ). So, increasing the temperature will be considered as an external stress on the system.
According to Le Chatelier's principle, when a system at equilibrium is subjected to a stress, it will shift in a way that helps counteract the stress and re-establish equilibrium.
Since the reaction is exothermic, an increase in temperature will be considered as an excess of heat. To counteract this, the reaction will shift in the direction that absorbs heat, which is the endothermic direction.
In this case, the forward reaction (from PCl5 (g) to PCl3 (s) + Cl2 (g) ) is the endothermic direction, which means that increasing the temperature will shift the equilibrium to the left side (forward reaction).
Therefore, when the temperature of the system PCl5 (g) = PCl3 (s) + Cl2 (g) + 92.5 kJ is increased, the Le Chatelier's shift will cause the equilibrium to shift to the left.