Which substance(s) listed below would be expected to have a standard molar Gibbs Free-Energy of formation equal to zero, D G f = 0?
I. Na + (aq)
II. O₂(g)
III. H₂ O ( )

Question

Which substance(s) listed below would be expected to have a standard molar Gibbs Free-Energy of formation equal to zero, D G f = 0?
I. Na + (aq)
II. O₂(g)
III. H₂ O (  )

Quizplus · Accepted Answer

The standard molar Gibbs Free-Energy of formation for an element in its standard state is equal to zero. Oxygen gas (O₂) is an element in its standard state, so its D G f is equal to zero. Na⁺ and H₂O are not elements in their standard states, so their D G f values are not necessarily zero.

Which Substance(s) Listed Below Would Be Expected to Have a Standard