1. The problem statement, all variables and given/known data Calculate how much energy is required to evaporate 3.6x10^14kg of water. (Original question is that if the oceans cover about 70% of the Earth's surface and an average of 1m evaporates per year, find the the energy required to evaporate the calculated amount of water (given radius: 6400km).) 2. Relevant equations The assumption is that the evaporation is a simple function of heat. 3. The attempt at a solution By dimensional analysis, I came up with: [tex]E=m \delta T C_p[/tex] where E is the energy required, m is the mass, ΔT is the change in temperature and C is the heat capacity of water. But I'm not sure if I'm supposed to assume that water evaporates at 100°C. A quick search showed that water evaporates at all temperatures greater than 0°C and there are a bunch of other factors like pressure and such. It's more involved than what I have but we haven't gone into all that yet and I don't think we will for this course. So is the equation correct and if so, what should I be using for ΔT as I'm not given the average temperature of the oceans.