8.49

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Renee Delamater 2H
Posts: 31
Joined: Wed Nov 16, 2016 3:02 am

8.49

Postby Renee Delamater 2H » Tue Jan 23, 2018 10:25 pm

How do you find the change in internal energy with only a reaction and delta H given? It says "What is the change in internal energy for the reaction of 1.00 mol OF2? in the reaction OF2(g) + H2O(g) = O2(g) + 2H(g)." How do you find this for only 1 mole of one of the reactants?

mhuang 1E
Posts: 22
Joined: Fri Sep 29, 2017 7:05 am

Re: 8.49

Postby mhuang 1E » Tue Jan 23, 2018 10:35 pm

Because we're dealing with gases, use the ideal gas law: PV=nRT.
work=-p(delta v)=-(delta n)RT= -(1mol OF2)(8.314 JK^-1mol-^-1)(298K)=-2.48KJ
(Use 298K because we assume the rxn occurs at room temp.)
Because we are finding the change of internal energy:
(delta U)= q+ w= -318 KJ-2.48 KJ= -320KJ


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