Coffee Cup Calorimeter
A coffee cup calorimeter is a useful, simple device that can
be used to measure the temperature change that accompanies a reaction. Because
a styrofoam cup is a good insulator, the cup will absorb almost
none of the energy released (or supply almost none of the energy
absorbed) by the reaction taking place inside it. Thus, any change
in temperature is assumed to be due only to the reaction, and
the heat transferred in the reaction may be calculated.
Using the Calorimeter
First make sure that the calorimeter, the stirring rod, and
the thermometer or thermal probe are clean and dry. Do not use
an organic solvent such as acetone to dry the calorimeter, as
these solvents may dissolve the styrofoam.
Next, assemble the calorimeter.
Video: Assembling the calorimeter ( 3.52 M )
With the thermometer or thermal probe, measure the initial temperatures of the substances to be mixed.
If the substances have been standing in the laboratory, they
are probably at room temperature, but the temperature must still be measured accurately.
When performing the calorimetry experiment, remember to stir
the solution continuously and record a temperature at regular,
frequent intervals. Be sure the thermometer or thermal probe remains
in contact with the reacting materials.
Video: Calorimetry experiment ( 4.35 M )
Video ( 2.49 M )
In the video, a student is performing a calorimetry experiment. Explain what he forgot to do during this experiment. Answer
When should you stop taking readings during a calorimetry experiment?|
A. When the temperature has risen by five degrees.
B. When no further temperature change is observed.
C. Five minutes after the first temperature change is observed.
D. As soon as the temperature drops below room temperature.
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