PASCO ET-8499 Energy Transfer Calorimeter - Manual (Page 11)

Model No. ET-8499 Experiment 1: Heat of Fusion of Ice
9 ®
9. Dry off the ice with a paper towel, and then place it in the Calorimeter. Replace the lid and
watch the temperature of the water. Gently swirl the Calorimeter every 10 seconds to ensure
an even temperature.
10. Continue to gently swirl the Calorimeter every 10 seconds as you watch the temperature
decrease, until it reaches its lowest value. Lift the lid and look inside to see that all the ice has
melted. If not, replace the lid and continue. Record the lowest temperature.
11. Remove the inner cup and determine the mass of cup and water. Use this to calculate the mass
of ice you added.
Analysis
1. Calculate the change in temperature,
∆
T, of the cup and water.
2. Calculate the change in temperature of the melted ice water.
3. Calculate the total amount of heat, Q
lost
, lost from the cup and water. Use the proper specific
heat for each.
4. Calculate the total amount of heat, Q
gained
, added to the ice. You should have two terms.
5. What percentage of the energy supplied by the water and cup is delivered to the ice?
Calculate the percent difference.
6. Did the system "lose" energy or "gain" energy. Explain your results using the concept of
conservation of energy.
Questions
1. Why did we go to the trouble to start with water in the cup that was above room temperature?
What does that accomplish?
2. Why does Q for the aluminum cup include only the inner cup? Why do you not include the
spacer? Why is the spacer not made of aluminum?
3. Why does the gap between the inner and outer cup provide insulation? In theory, what would
ideally be in this gap?
4. Why did you wipe the water off the ice to dry it before adding it to the cup.
% difference
Q
lost
Q
gained
–
Q
lost
------------------------------------ X 100(%) =