Lake Erie contains about 4.8 x 10^17 grams of fresh water. Assume that the lake has frozen solid and that the ice starts off at -3 C. How much energy would the lake need to absorb from the Sun to cause it to evaporate completely?

Each gram of water will require 721.5 calories to heat up, melt and evaporate. That equals 3109 joules. Multiply that by the mass of water in the lake.

Is this correct?
(721.5c)(4.8 x 10^17) = 3.46 ^17