The densities of ice and water at 0*C are 0.9168 and 0.9998g/cm3. The latent heat of ice is 80cal/g. What is "delta"H and "delta"U (enthalpy and internal energy, respectively) when 1kg of ice is melted? I'm really confused on which formulas to use and if the densities are even relevant to this question. One of the formulas I was looking at are "delta"U = m x Cv x "delta"T (but because "delta"T is zero, this would make the variation of internal energy 0, which doesn't make much sense, does it?) Any help would be greatly appreciated!! Thanks in advance. Eric ADDITION: I just read the FAQ sticky note for this section and I'm sorry for not including my attempts thus far. I'm new to the forum and wasn't completely aware of what's expected. So here goes: One thing I tried was using the formula described above but it doesn't seem to make sense that the internal energy wouldn't change. Another formula I tried was the following: H = U + pV Where V = 0.9168g/cm3 / 1000g = 9.168 x 10^-4 cm3 But now I still don't have V and the question doesn't specify the pressure (I could assume we're at atmospheric pressure, but I'm still no further ahead) I feel like the answer is really simple and I'm just making it complicated. Any insight would be great!!