To determine the amount of heat needed to evaporate a certain amount of water at its boiling point, we use the equation,
H = m(Hv)
where H is the heat, m is the mass (in grams), and Hv is the latent heat of vaporization. Substituting the known values,
H = (105 g)(540 cal/g)
H = 56700 cal
H = 56.7 kcal
Answer: 56.7 kcal
