General chemistry: which one of the following substances does NOT have a heat of formation equal to?

Question

at standard conditions?

F2(g), Cl2(g), Br2(g), I2(g)

and why?

Answer 1

Atomic elements in there natural state have heat of formation of 0 at standard conditions.

However Br2 and I2 are a liquid and a solid at standard conditions.

As Br2 and I2 are gases for this question then they would of needed to over come there latent of that phase change and hence there heat of formations are not equal (to zero?)

Answer 2

the question is flawed.

both iodine and bromine are NOT gases at standard conditions - bromine is a liquid and iodine is a solid.

Answer 3

I2(g) at 62.42 kJ/mol. This is because the gaseous state is not the standard state for iodine. The solid, standard state for I2(s) is 0 kJ/mol.