Specific and Latent Heat

Learning Goal: I’m working on a physics exercise and need an explanation and answer to help me learn.

Goals:Learn about temperature and heat

Determine what is necessary to change the temperature
of an object.
Enhance laboratory skills using the calorimeter.

In this experiment we will observe the change in temperature of
a known mass of a particular material as it absorbs heat. The
property of this material to absorb and store heat is called its
specific heat capacity or sometimes it is called its thermal
capacity. The symbol used to represent this value is c.

The property of an object to store heat takes on different
values for different materials. In order to study this property
we will use conservation of energy and the fact that a hot
object transfers its heat to a cooler object. In this case we
will assume that the heat energy lost by the hotter object will
be equal to the heat energy gained by the cooler object.

Procedure:

1. Fill a glass beaker 2/3 full of water, and set it over a
Bunsen burner to boil.

2. While waiting for the water to boil, obtain metal a metal
sample, a Styrofoam cup, and a calorimeter. Do not throw
away the Styrofoam cup, and do not punch holes in it (we
reuse them).

3. Measure and record the mass of the metal cube (Mmetal), the
mass of the Styrofoam cup (Mcup).

4. Fill the Styrofoam cup 2/3 full of cool tap water.
Measure and record the total mass of the cup and the
water (Mcup&water). Later we will subtract the mass of the
empty cup from this value to get the mass of the cool
water (Mwater).

5. Suspend the metal into the boiling water, without
allowing the metal to contact the cup. Make sure the
metal in completely submerged in the boiling water. Keep
it there for 1 minute. Measure and record the
temperature in Fahrenheit of the boiling water (Thot) (do
not assume you know this value – use the thermometer). We
use Fahrenheit since 0.1°F is smaller than 0.1°C, thus
making a more precise measurement. Make sure to stir the

Physics 110 / Physical Science 111 Lab Manual
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water with the thermometer to get a consistent
measurement.

6. Measure and record the temperature in Fahrenheit of the
cool water (Tcool) just prior to placing the hot metal into
it.

7. Take the metal cube out of the boiling water, and
transfer it to the cool water in the Styrofoam cup of the
calorimeter, and then place the lid on top of it to
prevent heat loss. Stir the cool water with the
thermometer, keeping a close eye on the temperature
measurement. Make sure the thermometer is not in contact
with the metal. Record the maximum temperature in
Fahrenheit of the cool water (Tfinal).

Analysis:
8. Calculate the change in temperature for the water, and
the change in temperature for the metal in Fahrenheit.
Since our equation has a ratio of temperature change, we
do not need to change the temperature change into
Celsius!

9. Apply the conservation of energy idea to the equation
Q = mc∆T for the hot metal and the cool water, and find
the specific heat of the metal. Assume the specific heat
of water is 1 cal/g°C. The heat lost by the metal is
equal to the heat gained by the cool water.

10. Compare the observed value with the known value for the
specific heat of the metal (calculate a percent error).

Repeat steps 1 thru 10 for 3 trials and the additional metals
available. Make sure to pour out the warm water from the
Styrofoam cup and replace it with fresh cool tap water each
time.
mmetalcmetalΔTmetal=mwatercwaterΔTwater
cmetal=mwatercwaterΔTwater
mmetalΔTmetal
observed −actual
actual x100%

Physics 110 / Physical Science 111 Lab Manual
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Data Sheet: Specific Heat Capacity
Name _______________________
Date _______________________
Lab Partners _______________________
Instructor Signature _______________________

Metal:
Aluminum

Iron

Brass
Trial: 1 2 3 1 2 3 1 2 3
mmetal (x.x g)=
mcup (x.x g)=
mcup & water (x.x g)=
Thot (x.x °F)=
Tcool (x.x °F)=
Tfinal (x.x °F)=
mwater (x.x g)=
∆Twater (x.x °F)=
∆Tmetal (x.x °F)=
cmetal (x.xxx cal/g°C)=
cmetal ave (x.xxx cal/g°C)=
cactual (x.xxx cal/g°C)= 0.215 0.108 0.092
% error (x.x %)=

Physics 110 / Physical Science 111 Lab Manual
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Physics 110 / Physical Science 111 Lab Manual
Page 69
Latent Heat of Fusion

If a material undergoes a phase change, for example by
melting or boiling, the internal energy of the material
changes, but its temperature does not. Because this energy
change does not alter the temperature of the material, we
refer to this heat as latent, or “hidden”, heat. In the
case where a solid changes into a liquid (melting) we refer
to the latent heat of fusion, which is defined as the
amount of heat necessary to change one gram of a solid into
a liquid without a temperature change. The latent heat of
fusion literally means “hidden heat which causes melting”.
The heat required to completely melt a given mass, of a
substance is given as

In this experiment, you will determine the latent heat
of fusion for water ice. You will add ice to room
temperature water. Heat is removed from the water to both
melt the ice and warm the melted ice water to an
equilibrium temperature. From the conservation of energy
we can write,

where , and

Even though the initial temperature of each material is
different, they end up at the same the final temperature.

H=mLf
Hlost by water =Hgained by ice
Hlost by water =Hto melt ice +Hto raise ice water temperature
mwater cwater ΔTwater =miceLf +micecwater ΔTice→water
Lf =mwater cwater ΔTwater −micecwater ΔTice→water
mice
ΔTwater =Tinitial −Tfinal ΔTice→water =Tfinal −32°F

Physics 110 / Physical Science 111 Lab Manual
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Procedure:

1. Measure and record the mass of an empty Styrofoam cup.

2. Fill the cup with warm tap water.

3. Measure and record the mass of the cup and water
combination.

4. Place cup into calorimeter.

5. Obtain ice cube that has been left out at room temperature
for a long time period (not fresh out of the freezer), in
this case it is assumed that the ice is 32.0° Fahrenheit.
Dry off the ice cube of any excess moisture.

6. Measure and record temperature in Fahrenheit of water in
the Styrofoam cup. We do this since 0.1°F is smaller than
0.1°C, thus making a more precise measurement.

7. The next sequence of events should occur very quickly.
Gently place dry ice cube into the calorimeter (Styrofoam)
cup and cover with lid. Stir with thermometer, avoiding
touching ice cube with tip of thermometer. Record the
lowest temperature in Fahrenheit when ice is completely
melted.Don’t continue to wait after the ice has
completely melted.

8. Measure and record the mass of the cup with water and
melted ice.

Calculations

9. Determine the change in temperature for the ice, and the
change in temperature for the water in Fahrenheit.

10. Calculate the change in temperature for the ice, and the
water, by multiplying the change in temperature in
Fahrenheit by 5/9 (subtracting by 32 is not required since
we are using a change in temperature).

11. Apply the measurements to the “big equation” and compare
your results to the actual value for the latent heat of
fusion of water
Lactual = 79.7 cal/gram

by calculating a percent error.

Physics 110 / Physical Science 111 Lab Manual
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Data Sheet: Latent Heat of Fusion
Name _______________________
Date _______________________
Lab Partners _______________________
Instructor Signature _______________________

Trial(#): 1 2 3
Mass of Empty Cup (x.x g):
Mass of Cup with Water (x.x g):
Mass of Cup with Water and Melted Ice (x.x g):
Temperature Start (x.x °F):
Temperature Finish (x.x °F):
Change in Temperature of Water (x.x °F):
Change in Temperature of Ice–>Water (x.x °F):
Change in Temperature of Water (x.xx °C):
Change in Temperature of Ice–>Water (x.x °C):
Mass of Water (x.x g):
Mass of Ice (x.x g):
Calculated Latent Heat of Fusion (x.x cal/g):
Average Observed Latent Heat of Fusion (x.x cal/g):
Actual Latent Heat of Fusion (x.x cal/g):
Latent Heat Error (x.x %):