A Substance Has a Melting Point of 20°C and a Heat

Multiple Choice

A substance has a melting point of 20°C and a heat of fusion of $3.6 \times 10 ^ { 4 } \mathrm {~J} / \mathrm { kg }$ The boiling point is $150 ^ { \circ } \mathrm { C }$ and the heat of vaporization is $7.2 \times 10 ^ { 4 } \mathrm {~J} / \mathrm { kg }$ at a pressure of one atmosphere. The specific heats for the solid, liquid, and gaseous phases are 600 J/kg ? K (solid) , 1000 J/kg ? K (liquid) , and 400 J/kg ? K (gaseous) . How much heat is given up by $2.80 \mathrm {~kg}$ of this substance when it is cooled from 170°C to 86°C at a pressure of one atmosphere?

A) 400 kJ
B) 200 kJ
C) 300 kJ
D) 440 kJ
E) 640 kJ