Question

A piece of aluminium of mass 260g is cooled in a freezer. It is then dropped into 140 g of water at 5°C, causing 4.0g of water to freeze. Determine the temperature inside the freezer​

Answer 1

To determine the temperature inside the freezer, you need to calculate the enthalpy of fusion of the 4g of water that froze. The enthalpy of fusion of water is 334 J/g. Thus, the total enthalpy of fusion of the 4g of water is 334 J/g × 4 g = 1336 J. The total heat gained by the water and aluminium is the enthalpy of fusion of the water plus the heat gained by the aluminium by cooling it in the freezer. Since the heat gained by the aluminium is equal to the heat lost by the water, the temperature inside the freezer can be calculated using the equation Q = mcΔT, where Q is the heat transfer, m is the mass of the aluminium, and ΔT is the change in temperature. Thus, the temperature inside the freezer is 1336 J / (260g × 0.90 J/g°C) = 6.2°C