Relationship Between K and Heat
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Relationship Between K and Heat
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?
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Re: Relationship Between K and Heat
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.
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Re: Relationship Between K and Heat
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.
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Re: Relationship Between K and Heat
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.
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.
Re: Relationship Between K and Heat
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)
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Re: Relationship Between K and Heat
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.
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