Heat is added to a 200.-gram sample of H2O (s) to melt the sample at 0°C. Then the resulting H2O () is heated to a final temperature of 65°C. Determine the total amount of heat required to completely melt the sample. Heat is added to a 200.-gram sample of H2O (s) to melt the sample at 0°C. Then the resulting H2O () is heated to a final temperature of 65°C. Determine the total amount of heat required to completely melt the sample.

The heat is added to 200g ice at 0ºC to make the ice become water. there is no increase in temperature. the heat added is equal to the number of moles of ice melted x molar heat of fusion of ice, 6.01kJ/mole.

200g / 18g/mole = 11.11moles ice

11.11moles x 6.01kJ/mole = 66.78 kJ heat just to melt the ice to water

if you are just looking for the heat to melt the sample of ice, this is where you stop.

if you need to determine the heat to melt the ice AND raise the temperature, this is what you require

the second phase is raising the temperature of the water to 65ºC. this is equal to the mass of the water x specific heat of water x change in temperature

200g x 4.187J/g-ºC x 65ºC = 54431J or 54.431kJ energy to raise the water from 0ºC to 65ºC

the total heat required to melt the ice and then raise the temperature to 65ºC:

66.78kJ + 54.431kJ = 121.21kJ heat