Intermolecular
Forces
Taylor Fitzgerald
April 8, 2014
CHE1020
Spring 2014
TO: Professor Michelle Sama
FROM: Taylor Fitzgerald, CIT student
LAB PARTNER: Ashley Casey
DATE: April 8, 2014
SUBJECT: Intermolecular Forces
1)
Droplet
Weight
Droplet Width
Water
Acetone
Glycerol
0.05 cm
Isopropyl
Alcohol
0.05 cm
0.30 cm
0.80 cm
2.90 cm
2.00 cm
1.00 cm
0.40 cm
2)
Water
17
Number of Droplets
Isopropyl Alcohol
21
3)
Number of
Droplets
Evaporation
Time
Water
Acetone
Glycerol
1
Isopropyl
Alcohol
1
1
9 minutes
23 seconds
0 minutes
58 seconds
4 minutes
51 seconds
>9 minutes
23 seconds
1
4)
No table
5)
Observations
Water
Floats
Isopropyl Alcohol
Immediately sunk
Under Tension?
Yes, quickly
No
Glycerol
Expanded quickly
from where the
pepper was
shook, and it was
floating
Yes, slowly
1
CHE1020
Spring 2014
QUESTIONS:
1. Why did the droplets on the wax paper form different sized droplets?
Explain in detail what could be occurring to dictate droplets sizes.
 The droplets on the wax paper formed different size droplets because
of the product that they were. They all expanded. What could/might
dictate the droplet sizes are the surface tension and the viscosity.
2. Based on the droplet test, which liquid appears to have the greater
surface tension and greater intermolecular forces? Why?
 Isopropyl Alcohol appeared to have the greater surface tension and
intermolecular forces. More drops could fit on the penny verses the
water.
3. What forces are present that can explain why a paper clip floats on the
surface? What do you think will happen if you did the same experiment,
but used Isopropyl Alcohol instead?
 I think hydrogen bonding was present, hence why the paper clip
floats. I think the Isopropyl Alcohol would allow it to float because
there are more hydrogen atoms.
4. Determine if each of the liquids tested are polar or non-polar:
 Water (H2O): Polar
 Isopropyl Alcohol (C3H7OH): Non-polar
 Acetone ((CH3)2CO): Polar
 Glycerol (C3H8O3): Polar
5. Which of the liquids you tested displayed the greatest surface tension?
 Water: H20
6. How do you observations of surface tension and determination of polarity
relate to molecular attractions in your liquids?
 All the liquids that were polar had surface tension.
7. Below is a list of relative masses for each molecule we have been testing.
Recall that molecules with higher masses tend to have higher melting
points as long as their intermolculer forces are the same. Look up the
boiling points of each substance and record these values along with the
masses given below. What conclusions can you make about the boiling
point?
 The higher the boiling point, the higher the surface tension would be.
Masses
Boiling Point
Water
Acetone
18 g/mol
100 ˚C
58.08 g/mol
56 ˚C
Isopropyl
Alcohol
60.1 g/mol
82.5 ˚C
Glycerol
92.09 g/mol
290 ˚C
2