Lecture Question

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alanaarchbold
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Joined: Fri Sep 28, 2018 12:27 am

Lecture Question

Postby alanaarchbold » Tue Jan 29, 2019 10:00 pm

In one of the examples from Monday's lecture, O2 didn't have any delta HF value. I was wondering why that is?

Jordan Lo 2A
Posts: 85
Joined: Fri Sep 28, 2018 12:25 am

Re: Lecture Question

Postby Jordan Lo 2A » Tue Jan 29, 2019 10:12 pm

If you mean delta H formation, I think it's because we measure delta H formation relative to what the compound "normally" is. At 25 degrees Celsius and 1 atm, oxygen is usually O2(g). So, it doesn't take any additional energy to transform O2(g) from O2(g)

Max Hayama 4K
Posts: 63
Joined: Fri Sep 28, 2018 12:16 am

Re: Lecture Question

Postby Max Hayama 4K » Tue Jan 29, 2019 10:12 pm

The reason why O2 has a standard enthalpy of formation of 0 is because diatomic oxygen is the most stable in this form, therefore it requires no change to achieve this state!

Sophia Ding 1B
Posts: 62
Joined: Fri Sep 28, 2018 12:16 am

Re: Lecture Question

Postby Sophia Ding 1B » Wed Jan 30, 2019 2:03 pm

Yeah just to re-iterate, the standard enthalpy of formation has to always do with getting something to its most stable form; so for diatomic molecules (like O2) it is already in its most stable form, thus its standard enthalpy of formation would be 0.


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