Determining binding energy from latent heat of vaporization

[dav2008]

The measured value of the latent heat of vaporization of argon (at 1 atm) is
6.43 kJ/mol. Use this to estimate the binding energy.
(Given answer: 0.059 eV)

[Boiling point @ 1atm: 87.3K]

My initial approach was that since 6,430 joules worth of bonds had to be broken for a mole of Argon to vaporize, then to obtain the binding energy I could just divide the latent heat by the number of molecules in a mole. This gave me an incorrect answer of .067 eV and is clearly an oversimplified approach.Any thoughts?

Edit: Never mind I got it.

I forgot to subtract the work that goes into the expansion of the gas, and that it's the change in internal energy that's at question.

 

[Almsco]

After factoring in the work done in expansion, I get 0.059 eV as the binding energy.