University of Virginia
Physics Department

## Heat of Fusion

A Physical Science Activity

### Student Activity

Materials

• 2 Styrofoam cups (large)
• Balance for mass measurement
• 100 mL graduate cylinder
• 50 g ice
• Thermometer
• Stirring rod
• 200 mL water
• Hot plate

Procedure

1. Heat 200 mL of water on a hot plate.
2. Mass an empty styrofoam cup. Record this measurement.
3. Keep the cup on the balance, and add ice until 50 g have been added to the empty cup.
4. Add the hot water to the second cup. Mass the cup with the water and record.
5. Measure and record the temperature of the hot water using the thermometer.
6. Add the ice to the hot water. Stir the ice until it has completely melted. DO NOT USE THE THERMOMETER TO STIR THE MIXTURE.
7. Measure and record the temperature of the water again.
8. Mass the cup containing the water and melted ice. Record this measurement.

Data Sheet

 Mass of empty foam cup (g) Mass of cup and ice (g) Mass of cup and hot water (g) Mass of water (g) Initial temperature of hot water (°C) Final temperature of water (°C) Final mass of cup and water (g)

1. Calculate the amount of heat lost by the hot water after the ice was added. Use the equation Q = mcDT where c is the specific heat capacity of water and is 4.184 J/g°C.

2. Calculate the amount of heat gained by the ice as it melted and then as the water increased to its final temperature.

3. Determine the amount of heat absorbed by the ice during the process. Use the answers to questions 1 and 2 to do this.

4. Calculate the experimental heat of fusion. Use the equation Q = mLf.

5. How does your experimental value compare to the theoretical Lf value for water? Explain any variation.

6. Write a general equation to determine the total heat necessary to melt ice into water.