Alabama Science in Motion
Latent Heat of Fusion
Latent Heat of Fusion
Purpose:
The purpose of this experiment is to measure the latent heat of fusion for water using standard calorimeter
techniques. You will be adding ice to room temperature water and measuring the temperature change. Then you
will calculate the latent heat of fusion.
Materials/Equipment:
GLX
Styrofoam cup (Calorimeter)
Room Temperature Water
Temperature Probe
Plastic Spoon
Paper Towels
Top Loading Balance
Ice in Ice Bath
Pre Lab Questions:
1. What should be the temperature of the ice in the ice water bath? Explain your reasoning.
2. Will the temperature of the ice change as it is melting? Explain your reasoning.
3. Is the melting of ice an endothermic or exothermic process? Explain your answer.
4. Is the cooling of water an endothermic or exothermic process? Explain your answer.
Procedure:
1. Plug the temperature probe into the GLX.
2. Turn on the GLX. A graph will appear. Hit the Home key and scroll right to Digits then press the  key.
The GLX should be reading temperature.
3. Adjust the GLX to read more significant digits. Press the  key twice to show a drop down menu. Scroll
down to Data Properties. Press the  key and scroll down to Number of Digits. Increase the number of
digits to 2. Press F1 (OK). You now have the GLX set up to measure the temperature to hundredths of a
degree.
4. Obtain a Styrofoam cup containing ice and water. This mixture, called an ice bath, should have been sitting
in an insulated cooler for a short while to allow the ice and water to come to an equilibrium temperature of
0.00 °C. Measure the temperature of the ice bath and record in the data table.
5. Remove the temperature probe and dry it off.
6. Obtain an empty Styrofoam cup and measure the mass and record in the data table.
7. Fill the Styrofoam cup ½ full of room temperature water. Measure the mass of the water and cup and record
in the data table.
8. Next, place the temperature probe into the room temperature water. Allow the temperature to stabilize.
Record the initial temperature of the room temperature water.
9. Next, remove a small piece of ice from the ice bath. Dry the ice to remove excess water. Using a plastic
spoon, place the small piece of ice into the room temperature water. Carefully swirl the cup until the ice
melts. Do not use the temperature probe as a stirrer.
10. Continue adding small pieces of “dried” ice (using the plastic spoon) and melting it until the temperature of
the room temperature water decreases by at least 7°C. Each cube of ice should be allowed to melt before
adding additional ice.
11. After the last ice cube has melted, continue to monitor the temperature for several minutes to determine the
final equilibrium temperature. Record the final temperature of the water-melted ice mixture.
12. Measure and record the final mass of the cup/water/melted ice mixture.
May, 2013
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Alabama Science in Motion
Latent Heat of Fusion
Student Data Sheet
Name _____________________________ Partner’s Name(s) _____________________________________
Period/Block _______________________ Date ___________________
Pre Lab Questions:
1. What should be the temperature of the ice in the ice water bath? Explain your reasoning.
2. Will the temperature of the ice change as it is melting? Explain your reasoning.
3. Is the melting of ice an endothermic or exothermic process? Is the value of heat (Q) for this process positive
or negative? Explain your answer.
4. Is the cooling of water an endothermic or exothermic process? Is the value of heat (Q) for this process
positive or negative? Explain your answer.
Data:
Ice Initial Temperature, Tice
°C
Mass Empty Cup, mcup
g
Mass Cup and Water, mcup+water
g
Water Initial Temperature, Ti
°C
Water/Melted Ice Final Temperature, Tf
°C
Mass Cup + Water + Ice, mcup+water+ice
g
Calculations:
Mass of Water, mwater
Heat released from Water, Qwater
Mass of Ice, mice
kg
J
kg
Heat absorbed by melted Ice, Qice
J
Heat absorbed to melt Ice, Qmelt ice
J
Latent Heat of Fusion, Hf
J/kg
Standard Latent Heat of Fusion, Hf
J/kg
% Error
May, 2013
%
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Alabama Science in Motion
Latent Heat of Fusion
Calculations: Show all your work including formulas and units for numbers.
5. Calculate the mass of the room temperature water as mwater, in kg.
6. Calculate the amount of heat removed from the room temperature water as Qwater.
7. Calculate the mass of the ice added as mice in kg.
8. Calculate the amount of heat gained by the ice (after it melted) as it increased in temperature to the final
equilibrium temperature as Qice.
9. Using the Law of Conservation of Energy, calculate the amount of heat required to melt the ice as Qice melt.
10. Calculate the latent heat of fusion (Hf) in units of J/kg.
11. Calculate the percent error using the 3.34 x 105 J/kg as the standard heat of fusion for water.
Questions:
12. Which would be more effective in cooling a canned soda; 50 g of ice or 50 g of 0°C water? Explain your
answer in terms of heat.
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Alabama Science in Motion
Latent Heat of Fusion
13. After a long winter, the top layer of a lake may be frozen. As the warm weather arrives, it may take several
weeks for the air temperature by the lake to reach the temperature farther inland. Explain the reason for this.
14. As a 24.0 ton piece of glacier melts, how much heat does it absorb from the environment? Assume the
glacier is composed of pure water. 1 ton has a mass of 907.2 kg.
15. A student fails to dry the ice cubes before placing them into the cup of water. How will the student’s
calculated value for heat of fusion be compared to the standard value?
May, 2013
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Alabama Science in Motion
Latent Heat of Fusion
Heating Curve for Water
150
Temperature, °C
100
50
0
-50
May, 2013
Energy, J
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