thermodynamic numerical

[rabea]

hey guys,
this is someones question and i dont know the answer so could anyone of u plz answer it for me??ASAP.thanx in advance.
i was trying to solve some thermodynamic numericals for my test next week and i couldn't solve this one.
A mass of liquid with volume V completely turns into a gas of volume V' at a constant external pressure P and temperature T.
The latent heat of vaporisation is L for the given mass.
what will be the change in the internal energy of the system??

a)PV'-PV

b)L-PV'+PV

c)zero

d)L+PV'-PV

take care

[Fu-Kwun Hwang]

The work done is P(V'-V)
vaporisation process require energy L
so energy loss is P(V'-V)+L

[atifali12]

vry nice post good