Specific Heat Lab
One property of a substance is the amount of energy that it can absorb per unit mass. This property is
called specific heat, Cp. The specific heat is the amount of energy, measured in joules, needed to raise
the temperature of 1 kg of a material 1oC (1K).
A calorimeter is a device that measures the specific heat of a substance. The calorimeter insulates the
water-metal system from the environment, while absorbing a negligible amount of heat. Since energy
always flows from a hotter object to a cooler one (the object with an absence of heat) and the total
energy of a closed, isolated system always remains constant, the heat energy, Q, lost by one part of
the system is gained by the other.
Qlost by metal = Qgained by water
In this lab, you will determine the specific heat of two different metals. You heat a metal to a known
temperature and put it in the calorimeter containing a known mass of water at a measured
temperature. You measure the final temperatue of the water and material in the calorimeter. Given
the specific heat of water (4.18J/g°C) and the temperature change of the water, you calculate the heat
gained by the water (heat lost by the metal).
Remember Q=mCpT
Materials
Temperature probe and Lab Quest, calculator, calorimeter, 250mL beaker, tap water, hot plate,
balance, metal objects, string or crucible tongs
Procedure - Safety equipment should be worn for this lab.
1. Fill the beaker half full with tap water. Place it on the hot plate and begin heating.
2. While you wait for the water to boil, measure and record the mass of the metal sample and the
empty calorimeter.
3. Set up the Lab Quest to collect data.
a. Plug the temperature probe into CH 1 (channel 1)
b. On the Meter screen, tap Rate.
c. Change the rate to 1 sample/second.
d. Change the length to 900 seconds. This will allow you to collect data for up to 15
minutes.
e. Select OK
4. Attach a 30cm piece of string to each metal sample. Lower the metal sample by the sting into
the boiling water. Leave the metal in the water for at least 5 minutes.
5. Fill the calorimeter half full of tap water. Measure and record the total mass in a data table.
6. Measure and record the temperature of the water in the calorimeter and the boiling water. Do
not let the temperature probe touch the hot plate or beaker. Place the probe in the calorimeter.
7. Begin data collection by pressing play ►.
8. Carefully remove the metal from the boiling water and quickly lower it into the calorimeter.
9. Gently stir the water in the calorimeter for several minutes with the stir rod. Do not let the
temperature probe touch the metal object.
10. Watch the thermometer and record the highest temperature that the water reaches. Once the
temperature drops 2°C from its highest point, you may stop data collection.
11. Verify your data with the graph on the Lab Quest.
a. From the Analyze menu, select Statistics and then Temperature
b. Record the minimum temperature as your initial temperature of the water.
c. Record the maximum temperature as the final temperature of the water.
12. Empty the calorimeter, rinse it, and repeat the experiment with a fresh sample of water.
Data and Observations
Data Table 1
Trial 1
Observations of metal
Mass of calorimeter (g)
Mass of calorimeter and water
(g)
Mass of water (g)
Initial temperature of water
(oC)
Trial 2
Temperature of hot metal (oC)
Final temperature of water and
metal (oC)
Mass of metal (g)
T metal (oC)
T water (oC)
Q water
Q metal
Cp metal
Type of Metal
Percent Error in Cp
Analysis and Conclusion
1. For each trial, calculate the mass of the tap water, the change in temperature of the metal, and
the change in temperature of the water in the calorimeter. Record these values in the data
table.
2. For each trial, calculate the heat gained by the water.
3. For each trial, calculate the specific heat of the metal.
4. For each trial, use the values for specific heat of a substance found in your book to calculate
the percent error between your value for specific heat and the accepted value for the metal.
5. If you had discrepancies between your values for specific heat of the metal samples and the
accepted value, suggest sources of error.
6. A 100.0g sample of a substance is heated to 100.0oC and put in a calorimeter containing
150.0g of water at 25oC. The sample raises the temperature of the water 32.1oC. Use the
values in your book to identify the substance.
Conclusion