Question

Calculate the amount of heat energy required to melt 20 grams of ice at 0°C and determine the final temperature of the resulting water if the enthalpy of fusion of ice is 6.01 kJ/mol and the specific heat capacity of water is 4.18 J/(g·°C).

Answer 1

First, we need to calculate the number of moles of ice. The molar mass of water  H2O  is approximately 18.015 g/mol.Number of moles of ice =  mass of ice  /  molar mass of water Number of moles of ice = 20 g / 18.015 g/mol = 1.11 mol  rounded to 2 decimal places Next, we will calculate the heat energy required to melt the ice using the enthalpy of fusion.Heat energy required to melt ice =  number of moles of ice    enthalpy of fusion Heat energy required to melt ice = 1.11 mol  6.01 kJ/mol = 6.67 kJNow, we will convert the heat energy from kJ to J.Heat energy required to melt ice = 6.67 kJ  1000 J/kJ = 6670 JSince the ice is at 0C and it is melting, the final temperature of the resulting water will also be 0C. The heat energy required to melt the ice is used to break the bonds between the water molecules in the ice lattice, not to increase the temperature of the water. Once the ice is completely melted, any additional heat energy would then increase the temperature of the water.