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Activity: Operating the EquipmentActivity: Operating the Equipment
MeasurementMeasurement
2-11-2
u As shown in the illustration, force water through the reflux condenser.
u For boiling point elevation, turn on the heater and use the Temperature Measurement
Setup to measure the temperature.
u For freezing point depression, turn on the auto stirrer and use the Temperature
Measurement Setup to measure the temperature.
u Use the measured changes in temperature to determine boiling point elevation and
freezing point depression.
u Compare the measured results with the results calculated from naphthalene molality.
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Other Things To Do
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í Measuring Data
u Measure the mass of the beaker used for creating the solution.
u Slowly pour the benzene into the beaker so it flows down the inside surface of the beaker.
u Measure the mass of the small amount of naphthalene being used.
u Dissolve the small amount of naphthalene to create a dilute benzene solution, and then
measure the mass of the solution.
u Calculate the molality of the naphthalene.
u Divide the dilute benzene solution between two flasks, pouring the solution slowly along
the inside surfaces of the flasks.
u Secure one of the flasks in the boiling point elevation system, and the other one in the
freezing point depression system.
í Calculator Operation
u Perform the following operation to prepare for temperature measurement using the
Temperature Measurement Setup.
Using E-CON
Using a Calculator Program
Find the applicable program in the Program Library (P.2-16-3), input it into your calculator,
and then run it.
u Display a graph of temperature change starting from the point that the solution is first
heated.
T(°C) :Temperature
t(s) :Time
T
1
(°C):Solution Boiling Point
u Display a graph of temperature change starting from the point that the solution is first
cooled.
T(°C) :Temperature
t(s) :Time
T
2
(°C):Solution Freezing Point
1 Benzene
2 Naphthalene
3 Beaker
4 Round Bottom Flask
5 Naphthalene-Benzene
Solution
u Consider how the molecular weight of naphthalene can be determined using the
measurement results.
u Consider why the cooling curve of freezing point depression is not clear.
u Create another dilute solution using a different solute, and determine the boiling
point elevation and the freezing point depression.
u Create another dilute solution using a different solvent, and determine the boiling
point elevation and the freezing point depression.
1 Reflux Condenser
2 Tap
3 Water Flow Direction
4 Open the tap.
For freezing point depression, use the mixing stick to stir the flask contents.
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1(CASIO)c(TEMP)b(°C) 5w240w1(YES)