The heat of fusion of a compound is 30 joules per gram. What is the total number of joules of heat that must be absorbed by a 15.0 gram sample to change the compound from a solid to a liquid at its melting point?
A. 15 cal.
B. 45 cal.
C. 150 cal.
D. 450 cal.
Multiply the heat of fusion (30 J/g) times the number of grams (15 g). Heat of fusion is the amount of heat needed to change a solid to a liquid at the melting point.
30 J/g x 15 g = 450 J/g