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### Le Chatelier's Principle on Temperature

Posted: Mon Jan 21, 2019 3:07 pm
Which is favored when the heat is lowered in a reaction? Would it move towards the exothermic reaction?

### Re: Le Chatelier's Principle on Temperature

Posted: Mon Jan 21, 2019 3:15 pm
If the reaction is exothermic, heat is released as a result of the reaction. Therefore, lowering heat is like removing a product and the equilibrium shifts toward the products.If the reaction is endothermic, removing heat is like removing a reactant, so the equilibrium shifts toward the reactants.

### Re: Le Chatelier's Principle on Temperature

Posted: Mon Jan 21, 2019 4:07 pm
Though it is not technically correct scientific notation, you can think about heat like its own species in an equilibrium equation. If a reaction is endothermic, ( H>0), think of heat as a reactant, and when exothermic ( H<0), consider heat a product. This makes the application of Le Chatelier's Principle much more straightforward, as a change in temperature can now be contextualized as a change in a reactant or product, which I personally find easier to contextualize.

For instance, take the endothermic reaction $A+B\rightleftharpoons C, \Delta H^{o}=+24.00 J$. This can be rewritten in the terms explained above to be: $A+B+\Delta H^{o}\rightleftharpoons C$.
For this new equation, an increase in temperature --> an increase in heat; thus product formation is favored. If temperature is decreased, heat decreases--> reactant formation. It's that easy!

### Re: Le Chatelier's Principle on Temperature

Posted: Mon Jan 21, 2019 8:54 pm
Heat can be seen as part of the reaction, with an exothermic reaction having heat in the products and an endothermic reaction having heat in the reactants. Thus, lowering temperature for an exothermic reaction will cause the reaction to sit to the right.

### Re: Le Chatelier's Principle on Temperature

Posted: Wed Jan 23, 2019 12:40 pm
When the reaction is exothermic that means heat is being released as a product. If you are lowering the temperature you are essentially removing heat and that means the reaction will favor the product.