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Rachel Yoo 1F
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Joined: Fri Sep 28, 2018 12:24 am


Postby Rachel Yoo 1F » Wed Feb 20, 2019 12:25 am

Which of the following compounds become less stable with respect to the elements as the temp is raised: (a) PCl5 (b) HCN (c) NO(g) (d)SO2?

Sam Joslyn 1G
Posts: 34
Joined: Fri Sep 28, 2018 12:20 am

Re: 4J.15

Postby Sam Joslyn 1G » Wed Feb 20, 2019 10:30 am

To solve this you would have to calculate the change in Gibbs free energy of the formation of the compound (so for PCl5 you would have the reaction P + 5/2(Cl2)-----> PCl5) then if delta G is negative it would be thermodynamically stable relative to its formation elements.

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Joined: Fri Sep 28, 2018 12:23 am

Re: 4J.15

Postby Saachi_Kotia_4E » Wed Feb 20, 2019 10:32 am

this would depend on what you get for the entropy of reaction. PCl5 is less stable at higher temperatures because the resulting entropy is negative. HCN is more stable at higher temperature because the entropy is positive.

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