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Name _______________________________________________________ Section_______
Problem Statement: How is heat transferred between substances?
I. Data Collection
A. Go to https://media.pearsoncmg.com/bc/bc_0media_chem/chem_sim/calorimetry/Calor.php. The
simulation will open to an image of the calorimeter setup, which is quickly replaced with a new
screen with an Overview page. You are welcome to read the Overview Page, and by clicking on the
Learning Outcomes tab near the top of the display, you may read the Learning Outcomes Page. After
reviewing these two pages click on the Experiment tab. When the screen changes the page will show
two buttons: Run Demonstration button and Run Experiment button. You are welcome to click on
the Run Demonstration button, but the instructions below are for the Run Experiment button. After
clicking on the Run Experimental button the screen will look like Figure I.
Figure I. Experimental Setup for the Calorimetry Simulation
The Experimental setup shows a beaker on a hot plate to the left, and a calorimeter on the right.
Below the beaker and hot plate are three tabs (Liquids, Solids and Solutions). In this activity you
will be using the Solids tab beneath the beaker and hotplate, and the Liquids tab beneath the
calorimeter.
B. Beneath the beaker and hot plate click on the Solids tab and select Ag. Adjust mass to 20.0 g
and adjust the temperature to 200. °C. Click the Next button in the left frame near the bottom of
the screen. Now click on the Liquids tab beneath the calorimeter and add 50.00 g of water and
adjust the water temperature to 20.00 °C. Record the beginning conditions in the Table I below.
Table I.
C. In the Run Experiment section click on the Start button. What do you observe happening?
Record the final conditions of Ag and the water in the table above.
After clicking on the start button the lid on the calorimeter closes and the temperature of the
water that contains the piece of metal begins to increase. This makes sense because the hot
piece of metal is added to the cool water.
II. Data Analysis and Interpretation
A. Which substance, Ag or water, loses heat when they are combined? Which substance, Ag or
water, gains heat when they are combined? Which process is endothermic and which is
exothermic?
The silver is losing heat, since it is at the higher temperature initially. The water gains heat as
it is at the lower temperature initially. The heat lost by the metal is exothermic, and the heat
gained by the water is endothermic.
B. Calculate the heat (q) transferred to or from Ag. Use the equation q = m C s
∆t (q is heat in
Joules, m is mass, C s
is the heat content, and ∆t is the change in temperature).
q = mass * C s
* ∆T
q = 20.0 grams * 0.23 5
J
g ˚C
- ( 23. 96 ˚C – 20 0 ˚C) = – 8.27 x 10
2 Joules
C. Calculate the heat (q) transferred to or from water.
q = mass * C s
* ∆T
q = 5 0.0 grams * 4.
J
g ˚C
- ( 23. 96 ˚C – 20.0 ˚C) = 8.28 x 10
2 Joule
Ag water
Mass 20.0 g 50.0 g
Initial Temp (^) 200. ˚C 20.0 ˚C
Final Temp 23.96 ˚C 23.96 ˚C
Change in Temp 176.04 ˚C 3.96 ˚C
Specific Heat (J g
1 )
In this experiment we used five times as much water, but kept the amount of Ag constant
and observe that the heat lost by the metal is equal and opposite to the heat gained by the
water.
Heat released by the hot metal:
q hot
= mass * C s
* ∆T
q hot
= 20 .0 grams * 0.23 5
J
g ˚C
- ( 22 .00 ˚C – 20 0 ˚C) = – 8.37 x 10
2 Joules
Heat absorbed by the cold water:
q cold
= mass * C s
* ∆T
q cold
= 100 .0 grams * 4.
J
g ˚C
- ( 22. 00 ˚C – 20 ˚C) = 8.37 x 10
2 Joules
III. Particulate Level View
A. Repeat the experiment you set up in I.B. above. This time be sure to check the box to
show the microscopic view. You may want to repeat the experiment with the box selected
to see all of the different behaviors. In the space below draw a picture depicting a
microscopic view of a piece of solid silver metal in liquid water.
B. In II. A. you indicated which substance lost heat and which substance gained heat when a
hot piece of silver metal is added to water at room temperature. Using words, and if you
like, pictures, describe how heat was transferred between the two substances. Be sure to
include what you observed happening to the atoms of silver and molecules of water,
during the period just after they were added to each other and until the final temperature
was reached, that would help explain how heat is transferred.
Here the metal atoms from the hot metal transfer energy to the water molecules
whenever a water molecule collides with the metal atom. The water molecule with
the additional energy collides with other water molecules to transfer energy. This
happens repeatedly as more collisions between water molecules and metal atoms,
and collisions between water molecules continue to occur. As water molecules collide
with the hot metal atoms the metal atoms lose energy and the water molecules gaain
energy, until everything in the system is at the same energy.
the value in the table on the previous page. Compare the molar heat capacity for each of the
metals.
For aluminum:
J
g ˚C
g
mol
J
mol ˚C
For copper:
J
g ˚C
g
mol
J
mol ˚C
For iron:
J
g ˚C
g
mol
J
mol ˚C
VI. Conclusions
A. Repeat the experiment for the unknown solid metals. Record the data you collect in the
following table.
B. Calculate values for the specific heats for the two unknown metals.
For Unknown I the heat gained by water :
q hot metal
= - q cold water
(mass * C s
* ∆T)
hot metal
= - (50.0 g * 4.
J
g ˚C
* (35.03 ˚C – 20.0 ˚C))
cold water
so the metal must have lost that much heat and the specific heat would be
(mass * C s
* ∆T)
hot metal
= – 1. 35 x 10
3 Joules
Unknown I water Unknown II water
m 20.0 g 50.0 g 20.0 g 50.0 g
Ti 200. ˚C 20.0 ˚C 200. ˚C 20.0 ˚C
Tf 26.44 ˚C^ 26.44 ˚C^ 22.18 ˚C^ 22.18 ˚C
∆t 173.56 ˚C 6.44 ˚C 178.82 ˚C 2.18 ˚C
Specific
heat (J
g
q
C
s
q
mass ∆T
3 Joules
20.0 · 1 73. 56 ˚C
J
g ˚C
For Unknown II the heat gained by water :
q hot metal
= - q cold water
(mass * C s
* ∆T)
hot metal
= - (50.0 g * 4.
J
g ˚C
* ( 22. 18 ˚C – 20.0 ˚C))
cold water
so the metal must have lost that much heat and the specific heat would be
(mass * C s
* ∆T)
hot metal
= – 4.56 x 10
2 Joules
C
s
q
mass ∆T
2 Joules
20.0 · 1 78. 82 ˚C
J
g ˚C
C. Based on the comparison you made in IV.D., estimate the molar heat capacity for each
unknown metal.
Assume the molar heat capacity is an average of the molar heat capacities of aluminum,
copper and iron: 25.
J
mol ˚C
D. Calculate the molar mass of each unknown metal.
For Unknown I
J
g ˚C
· MM = 25.
J
mol ˚C
MM = 64.
g
mol
For Unknown II
J
g ˚C
· MM = 25.
J
mol ˚C
MM = 195
g
mol
E. Assuming the unknown metals are pure substances, identify them. Show how you arrived at
your answers below.
Unknown I could be copper or zinc, while Unknown II could be platinum or gold.
