Specific Heat
Purpose:
Measure the specific heats several metals using a calorimeter.
Equipment: Calorimeter, thermometer, balance, metal shot (aluminum, lead, copper),
double boiler, and burner.
Procedure:
1) Set up: In this experiment you will measure the specific heats of lead,
aluminum, and/or copper and compare your results with accepted values.
The metals are in the form of small metal spheres known as "shot."
2) Heat the shot in a "double boiler" for 5-10 minutes. Assume the shot is
95°C after this time. By using a double boiler the shot remains dry. Cool
water will be placed in the inner vessel of the calorimeter. The hot shot
will then be added and the combination will be stirred until a final
equilibrium temperature is reached. The before and after temperatures for
each material must be noted. You must also determine the masses of the
shot, the water in the calorimeter, the inner vessel of the calorimeter (but
not the insulating ring), and any stirring rods that are used. The heat lost
by the shot will be equaled to the heat gained by the water and inner part
of the calorimeter to determine the specific heat of the metal.
Notes:
The calorimeter and stirring rods are made of aluminum, so use the
accepted value for the specific heat of those parts. The calorimeter is
filled with water, so use its accepted specific heat value. Assume that you
do not know what metal the shot is made from and calculate the specific
heat of the metal from your temperature data. After calculating the
specific heat of the metals, compare your value to the accepted values.
Accepted Values:
Substance
Lead
Copper
Aluminum
Water (15°C)
Ice (-5°C)
Specific Heat Capacity (J / kg C°)
128
384
900
4,186
2,090
Substance
Water
Latent Heat of Fusion (J / kg)
3.33x105
3) Calculations: If our calorimeter is a good thermal insulator,
conservation of energy tells us that all of the heat lost by our hot metal as
it cools goes into the water and calorimeter parts, making them warmer:
Q  0
QHot  QCold  0
7) Analysis:
a) Based on the definition of specific heats and the principle of
conservation of energy, derive an expression for the specific heats
of the metals.
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b) Use the expression you derived in #1 to calculate your
experimental value of the specific heats for each of the three
metals.
c) Compare your experimental results with the textbook values of
specific heats.
d) Explain any differences that you observed between your
measurements and the textbook values either as random errors
(which would be indicated in the sensitivity analysis) or systematic
errors?
Latent Heat of Fusion
Purpose:
Measure the Latent Heat of Fusion for water.
Equipment: Calorimeter, thermometer, balance, and ice.
Procedure:
1) Set up: The latent heat of fusion of water can be found by adding ice of
known temperature and mass to a calorimeter containing warm water of
known mass and temperature.
2) Measure the masses and temperatures of all the calorimeter components
(warm water, and inner vessel of the calorimeter) with a thermometer.
Assume the temperature of the ice is 0°C and add it to the warm water in
the calorimeter. When the ice has completely melted, note the temperature
of the water. It may be beneficial to plot the temperature as a function of
time. Measure the mass of the water with the melted ice in it - the
difference between its mass now and before yields the mass of the ice
added.
3) Analysis:
a) Based on the definition of specific heats, latent heat of fusion
and the principle of conservation of energy, derive an expression
for the latent heat of fusion of water. Consider the specific heats
and masses of the water, and metal of the calorimeter.
b) Use the expression you derived in #1 to calculate your
experimental value of the latent heat of fusion.
c) Compare your experimental results with the textbook values of
the latent heat of fusion.
d) Explain any differences that you observed between your
measurements and the textbook values either as random errors
(which would be indicated in the sensitivity analysis) or systematic
errors?
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