Temperature and Enthalpy

[105561735]

How does temperature affect the enthalpy change of a reaction, and what role does it play in Le Chatelier's Principle?

[106046096]

Hi! An increase in temperature will favor the forward reaction if the reaction is endothermic (ΔH > 0), and an increase in temperature will favor the reverse reaction if the reaction is endothermic (ΔH < 0). A decrease in temperature will favor the reverse reaction if the reaction is endothermic (ΔH > 0), and an increase in temperature will favor the forward reaction if the reaction is endothermic (ΔH < 0).

[Lan Wei 3I]

According to the Le Chatelier's Principle,

in an endothermic reaction, as temperature increases, the reaction will shift right (towards the product)
in an exothermic reaction, when temperature increases, the reaction will shift left (towards the reactants).

Lastly, generally, as temperature increases, the enthalpy also increases.

[Isabelle Huerta 2I]

The way that temperature affects enthalpy change is by playing a role in the energy levels of the reactions and the products. Increasing temperature will typically have a favor over endothermic reactions because it will result in more thermal energy proceeding the reaction. Exothermic reactions are typically favored by decreased temperature, opposite of endothermic. In terms of Le Chatelier's Principle, temperature is a factor that can change the equilibrium of a reaction. Meaning that when temperature increases, the equilibrium will move in the direction where heat is being absorbed so work against the rise in temperature. Or when temperature decreases, the equilibrium moves in the direction where heat is being released so it can work against the decrease in temp.