Question

150g of ice is removed from a freezer at a temperature of -15°C. The ice is left, eventually reaching thermal equilibrium with its surroundings at a temperature of 21°C. If the latent heat of fusion for water is 336 kl/kg, the specific heat capacity of ice is 2100 J/kg.°C, and the specific heat capacity of water is 4200J/kg.°C, how much energy goes into the ice? Where does this energy come from?

Answer 1

q1 = heat added to raise T of ice @ -15 C to zero C.
q1 = mass ice x specific heat ice x (Tfinal - Tinitial) = ?
q1 = 0.150 kg x 2100 J/kg x [0 -(-15)] = ?
q2 = heat added to convert solid ice to liquid water.
q2 = mass H2O x heat fusion ice @ zero C.
q2 = 0.150 kg x 336 kJ/kg = ?
q3 = heat added to raise T of liquid water from zero C to 21 C
q3 = mass H2O x specific heat H2O x (Tfinal - Tinitial)
q3 = 0.150 kg x 4.2 kJ/kg x (21 - 0) = ?
Totol Q = q1 + q2 + q3
Post your work if you get stuck.