standard state of substances

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Peter Dis1G
Posts: 97
Joined: Fri Sep 29, 2017 7:04 am

standard state of substances

Postby Peter Dis1G » Tue Jan 16, 2018 3:10 pm

What are some standard states of substances that we have to remember? And what kind of question do we use standard states? I know that for O2 the standard state is O2, for carbon it is graphite. Thanks!

RyanS2J
Posts: 32
Joined: Thu Jul 27, 2017 3:00 am

Re: standard state of substances

Postby RyanS2J » Tue Jan 16, 2018 3:20 pm

Some common ones are that H2, N2, O2, F2, Cl2, Br2, and I2 are the standard states of their respective elements. These standard states are often used in the calculation of standard reaction enthalpy.

Kailey Brodeur 1J
Posts: 34
Joined: Thu Jul 27, 2017 3:00 am

Re: standard state of substances

Postby Kailey Brodeur 1J » Tue Jan 16, 2018 3:41 pm

We also should know what physical state some of the common elements are in. For instance, we should know that lead, gold, and iron are solids at room temp. These standard states will be used in standard enthalpy of formation and can be used with Hess's Law to determine the standard enthalpy of essentially all reactions.

Chris Lamb 1G
Posts: 58
Joined: Fri Jun 23, 2017 11:39 am

Re: standard state of substances

Postby Chris Lamb 1G » Tue Jan 16, 2018 8:42 pm

Most of the diatomic elements are gasses at their standard states; however I2 is a solid, and Br2 is a liquid.

Peter Dis1G
Posts: 97
Joined: Fri Sep 29, 2017 7:04 am

Re: standard state of substances

Postby Peter Dis1G » Tue Jan 16, 2018 9:41 pm

OMG lots to cover. Thanks!


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