Relationship Between K and Heat

[Kathleen Vo 1G]

What is the relationship between equilibrium constant K and delta H? And based on change in K in relation to heat, how do we determine if the reaction is exo- or endothermic?

[hiranya sundar 2D]

If K increases when we increase the heat the reaction is endothermic. If K decreases when we increase heat, the reaction is exothermic. There isn't really any concrete formula for finding K given only the heat, but heat does affect equilibrium.

[hiranya sundar 2D]

If K increases when we increase the heat the reaction is endothermic. If K decreases when we increase heat, the reaction is exothermic. There isn't really any concrete formula for finding K given only the heat, but heat does affect equilibrium.

[Anjana Shriram 2A]

If you're given the value of delta H, you can determine whether the rxn is endo/exo thermic directly. (Negative delta H = exothermic, positive delta H = endothermic).

If you don't know the value or sign of delta H, but you know how delta H affects K, you can still determine if the rxn is endo/exo thermic. If K increases as heat is added, then heat must be a reactant because adding it pushes the equilibrium forward towards products. Therefore, the rxn is endothermic. If K decreases as heat is added, then heat must be a product because adding it pushes the equilibrium towards reactants (smaller K value). Therefore, the rxn is exothermic.

[joannar]

When K is increased the reaction is endothermic and this can be expressed with a positive delta (example: ∆H=+3.19) and in reaction to this, when k is decreased the reaction is exothermic as it is releasing heat, so this can be expressed with a negative delta (example ∆H= -3.19)

[Isabelle Kim 3E]

Given that delta H is temperature independent, K would decrease as the temperature increases for an exothermic reaction. On the other hand, K would increase as the temperature decreases for an endothermic reaction.