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Equilibria shift with temp. increase 11.77

Posted: Tue Dec 05, 2017 11:07 pm
by Paula Dowdell 1F
Hi! I am having trouble figuring out how to approach this problem. Can someone walk me through their way of going about this problem? What is delta H?
Q: Predict whether each of the following equilibria will shift towards products or reactants with a temperature increase:
a) N2O4(g) ⇌ 2NO2(g), deltaH=+57kJ
b) X2(g) ⇌ 2X(g), where X is a halogen
c) Ni(s) + 4CO(g) ⇌ Ni(CO)4(g), deltaH=-161kJ
d) CO2(g) + 2NH3(g) ⇌ CO(NH2)2(s) + H2O(g), deltaH=-90kJ

Thanks!

Re: Equilibria shift with temp. increase 11.77

Posted: Tue Dec 05, 2017 11:15 pm
by Ammar Amjad 1L
Hey,

If a reaction requires heat, meaning it's endothermic, then heating it will favor product formation.

If a reaction gives off heat, meaning it's exothermic, then heating it will favor reactant formation.

If delta h is positive it means the reaction is endothermic, and if it's negative than it's exothermic.

a.) The reaction is endothermic, so adding heat will favor the formation of products
b.) It doesn't indicate whether or not this reaction is exothermic or endothermic, be we know that breaking a bond requires energy; therefore, it is endothermic. If the temperature is raised, the reaction will favor the products.
c.) This reaction is exothermic; therefore, raising the temperature will favor the formation of reactants.
d.) This reaction is exothermic; therefore, raising the temperature will favor the formation of reactants.

Hope this helps.

Re: Equilibria shift with temp. increase 11.77

Posted: Thu Dec 07, 2017 10:25 am
by Joyce Lee 1C
I like to think of heat as either a reactant or a product. So in an exothermic reaction, where heat is given off, heat can be thought of as a product. Thus, increasing heat will increase the amount of product, and the reaction will favor the reactants. Similarly, in an endothermic reaction, heat is a reactant and increasing it will favor the formation of products.