I'm just answering a thermodynamics problem of my Physics homework and I just can't get my head around it here. I'll give you the quesion here, and the reason I don't get it is because you're given the mass of the substamnce as opposed to the number of moles etc.... The latent heat of vaporisation for water at a pressure of 1 atmosphere and at 100 degrees C is 2268 J/kg. Assuming that the steam behaves as an ideal gasm calculate thee volume occupied by 1g of steam under these conditions. Hence calculate the work performed by 1g as it changes from liquid to gas. Using the forst law of thermodynamics, calculate the change in the internal energy of 1g of the water when it changes to gas. What does it mean by the latent heat as well? We've never used that term in lectures before. Thanks for your help!