Lab: Molar Heat of Fusion of Ice
The amount of energy required to convert a solid to a liquid, at constant temperature and pressure
depends on the amount of substance present. However, the amount of heat needed to melt a specific
amount, known as the heat of fusion, is always the same.
It is often useful to refer to the amount of heat needed per gram or per mole of substance. This is called
the heat of fusion. The heat of fusion is therefore the energy needed to change one gram of a solid into liquid
at the melting point and is specific to that substance. Placing a sample of ice in warm water causes heat to be
gained by the ice and lost by the warm water.
The heat lost by the warm water is equal to the heat gained by the ice: HEAT GAINED = HEAT LOST
Given: Specific Heat of Water = 4.184 J/g*°C Q = m * t * Cp
Purpose: To calculate the heat of fusion of ice.
Materials:
 100-200 ml foam cup
 100 ml graduated cylinder.
 thermometer
 electronic scale
 ice - about 15 to 20 grams (preferably crushed - should be dry)
 warm water (about 50°C)
Procedure:
 Work in groups of 3 to 4 students - No more than 4 students per group!
 Mass a foam cup.
 Heat water in a 250 ml beaker to approximately 50°C.
 Fill a foam cup with 100 ml of heated water measured with the graduated cylinder
 Mass the cup and water.
 Obtain some crushed ice - approximately 15 - 20 grams
 Quickly dry the ice with a paper towel to remove the sweat on the surface of the ice.
 Record the temperature of the water in the cup (this is temperature initial)
 Place the cup and water on the scale and add enough ice to increase the mass approximately 15 grams.
(note: the mass does not have to increase exactly 15 grams).
 Record the final total mass.
 Stir the ice until it all melts and record the final temperature in the cup the moment the ice has
completely melted.
 Perform 2-3 trials and average your results.
Discussion:
1. What is your estimate for the heat of fusion of ice in both J/g and kJ/mol?
Show all work and include all units.
2. Compare your results to the accepted values for the heat of fusion of ice which are 334 J/g and 6.019
kJ/mol. Calculate a % error and discuss at least 2 factors that might have contributed to the error.
Extra Credit! If an iceberg at 00C has a mass of 200,000,000 kg, how much heat would be required to melt the
entire iceberg to 12.50C (the average summer temp of the Puget Sound)? Hint - two step calculation!
Submit: Data table and discussion answers. Show all work and include all units. Submit individually.
Lab is due Wednesday April 3rd at the beginning of class.