Adaptation of
Experiment
9
Evaporation and Intermolecular Attractions
In this experiment, temperature probes are placed in various liquids. Evaporation occurs when
the probe is removed from the liquid’s container. This evaporation is an endothermic process that
results in a temperature decrease. The magnitude of a temperature decrease is, like viscosity and
boiling temperature, related to the strength of intermolecular forces of attraction. In this
experiment, you will study temperature changes caused by the evaporation of several liquids and
relate the temperature changes to the strength of intermolecular forces of attraction. You will use
the results to predict, and then measure, the temperature change for at least one other liquid.
Figure 1
AVAILABLE MATERIALS
interface (LabQuest?)
with temperature probe – stainless steel
or thermometer(s) – digital or glass
pieces of filter paper (2.5 cm X 2.5 cm)
small rubber bands
masking tape
CHEMICALS
Name – IUPAC (common)
1
2
3
n-pentane
n-hexane
n-heptane
4
methanol
(methyl alcohol)
ethanol
(ethyl alcohol)
1-propanol
(propyl alcohol)
2-propanol
(isopropyl alcohol)
5
6
7
Chemistry with Calculators
molecular
formula
C5H12
C6H14
C7H16
molar mass
(g/mol)
72.15
86.18
100.21
condensed structural formula
CH3CH2CH2CH2CH3
CH3CH2CH2CH2CH2CH3
CH3CH2CH2CH2CH2CH2CH3
CH4O
32.04
CH3OH
C2H6O
46.07
CH3CH2OH
C3H8O
60.10
CH3CH2CH2OH
C3H8O
60.10
(CH3)2CHOH
9-1
Experiment 9
8
9
10
11
12
13
14
15
1-butanol
(butyl alcohol)
2-methyl-2-propanol
(tert-butyl alcohol)
1-pentanol
(pentyl alcohol;
amyl alcohol)
1-pentanol
(isopentyl alcohol;
isoamyl alcohol)
1-hexanol
(hexyl alcohol)
C4H10O
74.12
CH3CH2CH2CH2OH
C4H10O
74.12
(CH3)3COH
C5H12O
88.15
CH3CH2CH2CH2CH2OH
C5H12O
88.15
(CH3)2CHCH2CH2OH
C6H14O
102.17
CH3CH2CH2CH2CH2CH2OH
2-propanone
(acetone)
1,2-ethandiol
(ethylene glycol)
1,2,3-propantriol
(glycerine)
C3H6O
58.08
CH3COCH3
C2H6O2
62.07
HOCH2CH2OH
C3H8O
92.10
1
4
5
6
2
HOCH2CHOHCH2OH or
C3H5(OH)3
7
3
13
14
9-2
15
8
9
10
11
12
Chemistry with Calculators
Evaporation and Intermolecular Attractions
PROCEDURE
1. You will work in small groups on this lab… BUT must do ALL of the processing as an
individual.
2. Obtain and wear goggles! CAUTION: The compounds used in this experiment are
flammable and poisonous. Avoid inhaling their vapors. Avoid contacting them with your skin
or clothing. Be sure there are no open flames in the lab during this experiment. Notify your
teacher immediately if an accident occurs.
2. Decide what chemicals you will use.

You need to test a minimum of three chemicals and should do multiple trials.

You may want to add a ‘predictive’ quality to your lab… i.e. test 3 chemicals and use
results to predict what would happen with a fourth chemical… then test the 4th chemical
and discuss the results. If you do this, you must have your prediction ‘stamped’ before
testing the 4th chemical.

Stock bottles of the chemicals are in the hood. Take only small amounts – just enough to
cover the thermometer tip/bulb. You should transfer the chemicals to labeled test tubes.
Keep the test tubes stoppered and in test tube racks.
3. Decide what tools you will use.

Option 1 – Temperature Probe(s) with Interface (LabQuest?)

Option 2 – Digital Thermometers and Timers
4. Decide how you will collect temperature and time data.

You will want to collect temperature data over time in order to determine the maximum
change in temperature (delta T). Think about what data you will need to record. Make a
data table to record this data. [Again – this must be done individually!]

To allow the evaporation to happen over a longer period of time, you need to use filter
paper to ‘hold’ some of the liquid. your thermometer with a square piece of filter paper
secured by small rubber bands as shown in Figure 1. Roll the filter paper around the
probe tip in the shape of a cylinder. Hint: First slip the rubber band up on the probe, wrap
the paper around the probe, and then finally slip the rubber band over the wrapped paper.
The paper should be even with the probe end.

You need to start with the thermometer in the liquid to establish a baseline temperature.
(? at least 30 seconds?) Stand the thermometer in the test tube containing the liquid you
are testing. Make sure the test tubes do not tip over.

Prepare a piece of masking tape, about 10-cm long, to be used to tape the probe in
position. After you’ve established a temperature baseline, remove the probe from the
liquid and tape it so the probe tip extends 5 cm over the edge of the table top as shown in
Figure 1.You need to remove the thermometer from the liquid and collect data for an
extended period of time… ? until the evaporation stops ? 5 minutes total? you’ll need to
decide.
Chemistry with Calculators
9-3
Experiment 9

Once you are done with the sample remove and dispose of the filter paper in a ziplock
bag your lab table. You will seal and throw away this bag at the end of the lab. Keep the
rubber band for additional testing.
5. Conduct your lab and collect your data 
6. Clean up.

Check with Ms. Smith about disposal of liquids.
SPECIAL NOTES:
This lab will be graded for both IB and grade-book. Your write up should include

a complete heading (name, date, title, group/partner)

a purpose

a summary paragraph of your procedure

raw data

a hypothesis (that includes your prediction for the fourth liquid, based on your evidence
for the first three liquids)

organized raw data

processed data

conclusion

evaluation
Pay particular attention to Data Collection and Conclusion/Evaluation. Pre-scored IB rubrics
are required for BOTH of these parameters.
9-4
Chemistry with Calculators