Specific Heat of Metals
GLX Version
Note: This is a Vernier lab that has been modified by ASIM for use with the GLX.
INTRODUCTION
Specific heat can be defined as the quantity of heat required to change the temperature of 1 gram of a
substance by 1 °C. In this experiment, you will determine the specific heat in a sample of copper
and then determine the specific heat of an unknown. According to the Law of Conservation of
Energy, energy or heat lost by one object must be transferred to or absorbed by another object. The
equation is hence, Q lost = -Q gained. To calculate the heat that flows into or from an object, you can
use the relationship
Q = Cp•m•T
where Q stands for heat flow, Cp is specific heat capacity, m is mass in grams, and T is the change
in temperature.
MATERIALS
Pasco GLX
temperature probe
250-mL beaker
Tongs
warm water
styrofoam cup
ring stand
utility clamp
metal samples
stirring rod
PROCEDURE
Part I Experiment Setup
1. Place a Styrofoam cup into a 250-mL beaker as shown in Figure 1.
2. Place the Temperature Probe into the Styrofoam cup.
3. Use a graduated cylinder to obtain 25.0 mL of water at room temperature from your teacher
and pour this into the Styrofoam cup.
4. Obtain one sample of both a known and an unknown metal.
5. Determine the mass of the known metal sample and your unknown metal; record in your data
table.
ASIM Specific Heat of Metals- GLX
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6. Prepare a hot water bath by heating at least 300 mL water in a 600 mL beaker on a hotplate.
Monitor the temperature using a thermometer clamped to a ring stand. Make sure the tip of
the thermometer does not touch any side of the beaker.
7. Turn on the GLX and connect the Temperature Probe y inserting it into temperature port 1
located on the left side of the GLX. A temperature vs. time graph should appear.
8. If a graph does not appear upon connecting the temperature probe, from the Home screen
, select Graph
. Make sure that temperature is displayed on the y-axis in degrees
Celcius.
9. When the temperature of your hot water bath reaches 85 °C, carefully hold your known metal
sample with a pair of tongs in the hot water bath for one minute, being careful not to allow
the metal to touch any side of the beaker.
Figure 1
10. Press Start
on the GLX to begin recording data. After a couple of seconds, immerse
your heated known metal sample into the cup of room temperature water. Use your
temperature probe to continually stir the mixture throughout data collection.
11. After 8 minutes of data collection, press stop
ASIM Specific Heat of Metals- GLX
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12. Auto scale the graph by pressing
13. From the Tools menu
.
, use the Smart Tool, select it with
, to examine the data
points along the displayed curve of temperature vs. time. As you move the cursor right or
left, the time (X) and temperature (Y) values of each data point are displayed. Find the
minimum or initial temperature for the water. This is the point on the graph just before the
metal is added. Move the cursor to the highest point of the graph and record this as the
maximum or final temperature. Record in data table. Use the equation T = Tf – Ti to
determine T, the change in water temperature.
14. Repeat the experiment using the unknown piece of metal. Be sure to get new water.
15. If time permits, repeat experiment with a second unknown.
ASIM Specific Heat of Metals- GLX
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SPECIFIC HEAT OF METALS
NAME ______________________________________
DATA AND CALCULATIONS
PARTNER’S NAME __________________________
PERIOD _________
DATE ___________________
TRIAL 1
Mass of sample, m
G
Initial water temperature, Ti
°C
Initial metal temperature, Ti
°C
Final temperature of mixture, Tf
°C
Change in water temperature, T
°C
Change in metal temperature, T
°C
Specific Heat of known metal, Cp
J/g °C
Percent Error
%
TRIAL 2
Mass of unknown sample, m
G
Initial water temperature, Ti
°C
Initial unknown metal temperature, Ti
°C
Final temperature of mixture, Tf
°C
Change in water temperature, T
°C
Change in unknown metal temperature, T
°C
Specific Heat of unknown metal, Cp
J/g °C
Identity of unknown metal
Percent Error
%
TABLE OF RELATIVE SPECIFIC HEATS
Aluminum
Carbon
Copper
Gold
Iron
Lead
Tin
Zinc
ASIM Specific Heat of Metals- GLX
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0.900 J/g °C
0.711 J/g °C
0.387 J/g °C
0.129 J/g °C
0.450 J/g °C
0.128 J/g °C
0.210 J/g °C
0.390 J/g °C
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CALCULATIONS FOR THE KNOWN METAL
1. Determine the heat gained by the water using the formula Q = Cp•m•T. Use 4.184 J/g C for
the specific heat of water. Assume that no heat is absorbed by the calorimeter.
Q gained by water = Cp(water) m(water) T(water)
Cp(water) = 4.184 J/g °C
T(water) = T final, mix – T initial, water
2. Determine the heat lost by the metal sample using the same heat equation. The specific heat for
metals is in the table on the first page of the data sheet.
Q lost by metal = Cp(metal) m(metal) T(metal)
T(metal) = T final, mix – T initial, metal
3. How does the heat lost compare to the heat gained?
CALCULATIONS FOR THE UNKNOWN METAL
4. Determine the heat gained by the water in Trial 2.
Q gained by water = Cp(water) m(water) T(water)
Cp(water) = 4.184 J/g °C
T(water) = T final, mix – T initial, water
5. Assuming complete transfer of heat from the metal to the water, determine the specific heat from
the metal.
Q lost by metal = Cp(metal) m(metal) T(metal)
Cp(metal) = what you are trying to solve
T(metal) = T final, mix – T initial, metal
ASIM Specific Heat of Metals- GLX
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6. Use the table of specific heats on the first page of the data sheet to determine your unknown
metal.
7. Using the accepted value for the specific heat of your metal, calculate the percent error for your
experiment.
QUESTIONS
1. How does the heat conductivity of the metals used in this experiment affect the accuracy of
the results?
2. Why is it important to heat the water bath to at least 85 °C before inserting your metal
sample? Explain.
3. What effect, if any, would a delay in transferring the metal sample into the calorimeter have
on the value of the change in temperature? On the specific heat value of the metal?
ASIM Specific Heat of Metals- GLX
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