Equilibrium constant and temperature

[deleted738762]

If a reaction is endothermic H=200kj. Then if I increase temperature then wouldn't that decrease the equilibrium constant? If Kc=products/reactants and heat in this case would count as a reactant, then wouldn't increasing heat decrease Kc because I think of it as a reactant.

Chad's quizzes states "If the forward reaction is endothermic, increasing the temperature increases the value of the equilibrium constant. This reaction has a positive enthalpy value so is endothermic."

Or should I not think of heat as a product or a reactant when changing Kc, but only when shifting the rate of the reaction?

Thanks

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[joker16z]

I'm pretty sure the answer is using Le Chatelier's principle: adding something to the reactants (heat) will cause an increase in the products, thereby increasing the equilibrium constant

 

[deleted738762]

I'm pretty sure the answer is using Le Chatelier's principle: adding something to the reactants (heat) will cause an increase in the products, thereby increasing the equilibrium constant

Ah that makes sense. So if exothermic, then I should decrease temperature so products are still being increased thereby increasing eq. constant.

 

[tyjacobs]

Ah that makes sense. So if exothermic, then I should decrease temperature so products are still being increased thereby increasing eq. constant.

Exactly. With temperature change you add heat to reactants side if its endothermic or add heat to products side if its exothermic. Then treat heat like a "reactant" (i.e. if temp goes up in exothermic rxn is = to adding more reactant so reaction shifts right)

 

[deleted738762]

Exactly. With temperature change you add heat to reactants side if its endothermic or add heat to products side if its exothermic. Then treat heat like a "reactant" (i.e. if temp goes up in exothermic rxn is = to adding more reactant so reaction shifts right)

Makes sense thanks.