Specific heat (c) Substances Solids Aluminum J/kg C kcal/kg°C 900 0.215 Concrete 840 0.20 Copper 387 0.0924 Glass 840 0.20 0.50 Ice (average) Liquids 2090 Water 4186 1.000 Gases Steam (100°C) 1520 0.363 ©theexpertta.com
Suppose you want to raise the temperature of a mass m of ice from T0 < 0 °C to T > 100 °C. In this problem, represent the heat of fusion as Lf, the heat of vaporization as Lv, and the temperatures at which the phase changes occur as Tf and Tv. The latent heats are Lf = 334 kJ/kg and Lv = 2256 kJ/kg. The specific heat of ice=ci, the specific heat of water =cw, and the specific heat of steam cs.
a) If the heat that must be transferred for this to happen, including the energy needed for phase change is
Q =mci ( Tf - T0 ) + m Lf + m cw ( Tv - Tf ) + m Lv + m cs ( T - Tv ).
How much heat, in kilocalories, must be transferred for this to happen to 0.175 kg of ice starting at a temperature of -20 °C and ending at a temperature of 130 °C?
b) How much time, in seconds, is required to do this, assuming a constant 20.0 kJ/s rate of
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