MCTP
Maryland Collaborative
for Teacher Preparation
 
 
Explaining Cold Boiling and Other Puzzling Observations
 
 
Thomas C. O'Haver
Department of Chemistry and Biochemistry
University of Maryland
College Park, MD 20742
(301) 4051831
to2@umail.umd.edu
 
 
NSF Cooperative Agreement No. DUE 9255745
 
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Chemistry 121/122            Name________________________________
Fall, 1994  
 
Explaining Cold Boiling and Other Puzzling Observations
 
Reflecting on the "Temperature and Molecular Motion" lab that you
did and the demonstration* you saw involving the "water aspirator" 
suction device and the flask of acetone:
 
1. What is going on at the molecular level when a liquid boils?
 
2.  How does your explanation of boiling account for the observed
facts that, at high elevations, water boils at a temperature lower
than 100 degrees C?
 
3. How does your explanation of boiling account for the observation
that a pressure cooker cooks foods more rapidly that boiling water
in an open container?
 
4.  What exactly did you observe in the laboratory demonstration
involving the "water aspirator" suction device and the flask of
acetone?
 
5.  What is going on at the molecular level that can explain the
puzzling observations in that laboratory demonstration?
 
* Note: Acetone is placed in a flask connected to a water
aspirator to pump (most of) the air from the flask.  The
the acetone boils vigorously sitting right there in a flask 
on the benchtop at room temperature.  As the boiling continues,
the acetone get colder and colder.
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Copyright 1994, Maryland Collaborative for Teacher Preparation