physics
posted by elisabeth .
how much heat is required to vaporize 7 grams of ice initially at 0 degrees celsius when the latent fusion of ice is 80 cal/g, the vaporization of water is 540 cal/g, and the specific heat of water is 1 cal/(g x C)?

Each gram of 0 deg. C ice requires 80 Cal to melt, 100 Cal to heat from 0 to 100 C as liquid water, and 540 cal to vaporize. That is a total of 720 calories.
Multiply that by the number of grams for the answer.