Enthalpy difference

Question

Both ΔvapH °(SeF4) and ΔfusH °(SeF4) are positive. but why is ΔvapH °(SeF4) more positive.

Answer 1

Hey Ahmed L.,

for water .delta.H(vap) is +540 cal g^-1

.delta.H(fus) is +80 cal g^-1

So which transformation requires (a lot!) more energy to accomplish, a vaporization or just a melting? Same for SeF4, for the same reasons!

?????

-- Cheers, --Mr. d.