Specific Heat of a Metal
Background:
On a sunny day, the water in a swimming pool may warm up a degree or two while the concrete around the pool may become too hot to walk on in your bare feet. This may seem strange because both the concrete and the water are being heated by the same source – the sun. This evidence suggests it takes more heat to raise the temperature of some substances than others. This, in fact, is true: The amount of heat that is required to raise the temperature of 1g of a substance by 1˚C is called the specific heat capacity, or simply specific heat, of that substance. Water, for instance, has a specific heat of 4.18J/g˚C. This value is high in comparison with the specific heats for other materials, such as concrete. In this experiment, you will use a simple calorimeter and your knowledge of specific heat of water to determine the specific heat of lead.
Materials:
600ml Beaker 400ml Beaker 100ml Graduated Cylinder
Balance 2 Foam Cups Large Test Tube
Thermometer Ring Stand Bunsen Burner
Ring Wire Gauze Striker
Utility Clamp Lead Copper and/or Aluminum
Procedure:
1. Heat a 600ml beaker three-fourths full of water until it is boiling.
2. While the water is heating, obtain and measure a sample of lead (anywhere from 80g to100g). Record its exact mass. Place the metal in a large test tube.
3. Set up your calorimeter by obtaining two foam cups from the teacher. Put one cup inside of the other and set them in a 400ml beaker.
4. Add exactly 100ml of cold tap water to the calorimeter. Measure and record the temperature of the tap water.
5. After the water is boiling, lower the test tube containing your metal sample into the boiling water. Securely clamp the test tube so that the bottom of the test tube is not touching the bottom of the beaker. Be sure the water level in the beaker is higher than the level of metal in the test tube.
6. Heat the metal for a minimum of fifteen minutes. Turn off the flame.
7. Using a paper towel to avoid burning yourself, carefully unhook the test tube and quickly pour the metal sample into your calorimeter. Immediately add the thermometer to the mixture. Measure and record the maximum temperature reached by the water in the calorimeter.
8. Pour off the water. Dry the lead by pouring it on a paper towel. Return the lead to its original container.
9. Repeat the above procedure with a second metal.
Data Table:
Trial 1 – Lead / Trial 2 – Copper or AluminumMass of Lead Sample
Mass of Water in Calorimeter
Initial Temperature of Water in Calorimeter
Initial Temperature of Lead Sample (Same as the Temp. of Boiling Water)
Maximum Temperature of Lead and the Water in the Calorimeter
Analysis:
1. Determine the temperature changes (ΔT) of the water and the metal sample for each trial.
2. Calculate the heat gained by the water in each trial. The specific heat of water is 4.18 J/g˚C.
3. Remembering that the heat gained by the water is equal to the heat lost by the metal, calculate the specific heat of the metal for each trial.
4. Use your textbook to find the accepted value for the specific heat for your two metals samples.
5. Calculate your percent error in the specific heat value of your samples that you determined experimentally. Use the accepted value that you found in the text as your theoretical value.
Conclusion:
1. You assumed that the initial temperature of the metal was the same as that of the boiling water. If the metal was actually at a lower temperature than the water, how would your value for the specific heat be affected?
2. Identify two other potential sources of error in this experiment.
3. Compare your experimental value for the specific heat of lead to the values obtained by your classmates. Can specific heat be used to identify substance?