A 6.00-kg piece of copper is placed with 2.00 kg of ice that is initially at - 20.0 °C. The ice is in
an insulated container of negligible mass and no heat is exchanged with the surroundings. After
thermal equilibrium is reached, there is 1.20 kg of ice and 0.800 kg of liquid water. What was
the initial temperature of copper? Specific heats: copper = 386 J/kg.K, ice = 2220 J/kg.K.