Standard Enthalpy

[Briana Yik 1H]

Can someone explain why standard enthalpy od O2 is zero? Thank you

[Iris Bai 2K]

The standard enthalpy of formation of O2 is 0, not the standard enthalpy (idk if that's even a thing). It's because oxygen is found naturally as a diatomic molecule, so it doesn't take energy to "form" it the way it's found in nature.

[Nandhini_2K]

O2 is 0 at standard state. All diatomic elements such as N2, O2, H2, will be zero and any single element from the periodic table.

[shaunajava2e]

All elements in their standard states (oxygen gas, solid carbon in the form of graphite, etc.) have a standard enthalpy of formation of zero, as there is no change involved in their formation.

[tierra parker 1J]

since 02 is normally found as a diatomic molecule so there is no need to form the molecule which gives a zero enthalpy of formation