Question

Deterine the heat of vaporization per mole of bromine.

Thank you, I thought there wasnt enough info!!. These high school Chem teachers need to check their questions before they hand them out !!

Answer 1

We will try to solve this problem by taking some literature values

Solid to liquid ----- fusion

liquid to gas ------- vaporization

solid to gas -------- sublimation

Or,

solid to liquid to gas ----- combination of fusion and vaporization

Now from literature we know,

with dH = enthalpy

dH(fusion) for Br2 = 10.6 kJ/mol

and,

dH(sublimation) = 40.1 kJ/mol

So,

dH(sublimation) = dH(fusion) + dH(vaporization)

substituting the values from above,

dH(vaporization) per mole of bromine = 40.1 - 10.6 = 29.5 kJ/mol