Transcript Intermolecular Forces - University of North Carolina Wilmington

CHM-102
Intermolecular Forces: Evaporation of
Alcohols and Alkanes
General Chemistry 101/102
Laboratory Manual
University of North Carolina Wilmington
UNCW
CHM-102
Intermolecular Forces
•
Purpose
 To study the effects of Intermolecular Forces, the
forces of attraction between molecules, on the
physical properties of alcohols and alkanes.
•
Safety Considerations
 Avoid inhaling the fumes from the alcohols and
alkanes.
 Wash the affected area thoroughly if you contact
any of the alcohols or alkanes.
 Dispose of all liquid waste materials in the bottle
labeled “organic wastes” in the fume hood.
UNCW
CHM-102
Intermolecular Forces
•
Procedure
 Connect the Tablet computer, Microlab unit, and
the temperature probe as shown in the illustration
below.
UNCW
CHM-102
Intermolecular Forces
•
Procedure
 To open the Intermolecular Forces experiment on
the computer, click on the Applications folder, and
select the Microlab prompt. Then double click the
“Time and Temperature” prompt as shown below.
UNCW
CHM-102
Intermolecular Forces
•
Procedure
 Click on the experiment entitled “Intermolecular
Forces-Evaporative Cooling”, as shown below.
UNCW
CHM-102
Intermolecular Forces
•
Procedure
 Wrap 1” square of filter paper around temperature
probe and secure it with a small rubber band.
 Place the temperature probe in the appropriate
sample liquid and wait 45 seconds before starting
data collection.
UNCW
CHM-102
Intermolecular Forces
•
Procedure
 Click the “Start”
prompt to begin
data collection
while the
temperature
probe remains in
the liquid for
another 45
seconds.
UNCW
CHM-102
Intermolecular Forces
•
Procedure
 Remove the probe from the liquid and place it
where it will remain undisturbed, such as on the
lab bench or towards the inside of the sink, with
the tip extending past the bench about 5 cm. Do
not touch the temperature probe while the liquid is
evaporating.
UNCW
CHM-102
Intermolecular Forces
•
Calculation
 Stop data collection when a minimum temperature has been
reached.
A
ΔT
B
UNCW
 The difference
in
temperature
between
point A
and point B
is ΔT for the
sample solution.