How much heat in kilojoules is evolved in converting 1.00 mol of steam at 145 °C to ice at −50.0 °C? The heat capacity of steam is 1.84 J/g °C and that of ice is 2.09 J/g °C.
Converting 1.00 mol of steam at 145 °C to ice at -50.0 °C involves the loss of
57.71 kJ of energy.
There are five heats to consider:
q1 = heat lost on cooling steam from 145 °C to 100 °C.
q2 = heat lost on condensing steam to water at 100 °C.
q3 = heat lost on cooling water from 100 °C to 0°C.
q4 = heat lost on freezing water to ice at 0 °C.
q5 = heat lost on cooling ice from 0 °C to -50.0 °.
The total heat evolved is