standard state of substances

[Peter Dis1G]

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]

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]

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]

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

[Peter Dis1G]

OMG lots to cover. Thanks!