Question

why the enthalpies of all elements in their standard states r zero?

please explain via example..

its urgent!

Answer 1

Hey mate here is your answer :

• Under standard conditions, oxygen can exist as O2(simply called oxygen) or as O3 (called ozone - but it is just an allotrope of oxygen). The O2 form is far more energetically stable than O3, so the standard state for oxygen is the common O2(g).

• 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.

Sorry Yash