Question

How much heat is required to convert solid ice with a mass of 870 g and at a temperature of -22.5 °C to liquid water at a temperature of 79.0 °C? (The specific heat of ice is cice = 2100 J/kgK, the specific heat of water is cwater = 4186.8 J/kgK, and the heat of fusion for water is: Lf = 334 kJ/kg.)

Answer 1

- 22.5 oC ------------ 0 oC   ---------- 79.0 oC

                      1           2           3

Q1 = m Cp dT

      = 870 x 2.10 x 22.5

     = 41107.5 J

Q2 = m x Lf

     = 870 x 334

      = 290580 J

Q3 = 870 x 4.1868 x 79

      = 287758.76 J

total heat = Q1 + Q2 + Q3

                  = 619446 J

heat required = 619.4 kJ