Lab 18 "Comparing Rates of Evaporation"

Chemistry Lab Handout 18 “Comparing Rates of Evaporation”

Your Name: ___________________________________ Role:______________

Lab Partners: ________________Role:_____ ________________Role:_____

Problem: How do intermolecular forces affect the evaporation rates of liquids?

Hypothesis: _______________________________________________________

_________________________________________________________________

Materials: distilled water ethanol

Isopropyl alcohol acetone pentane

5 dropper bottles stopwatch

hot water bath goggles

Caution:

Procedure:

1. Obtain goggles and wear them for the entire lab.

2. Place a single drop of one liquid on the lab table.

3. Start the stopwatch.

4. Draw a top view and side view of the drop.

5. Stop the stopwatch when the drop has completely evaporated. If it takes

longer than 6 minutes then stop at 6 minutes.

6. Record the time it took to evaporate in the data table. Record >360 s if it

took longer than 6 minutes.

7. Repeat the experiment with the other liquids.

8. Wipe off the lab table with wet paper towels and then dry the lab table.

9. Rank the liquids from #1, fastest to #6 slowest.

Data Table:

Observations:

Diagram:

Conclusion: _______________________________________________________

_________________________________________________________________

Questions:

1. Which liquid(s) have only dispersion forces at work?

2. What shape led to the fastest evaporation rate?

3. What attractive force increased surface tension in some samples?

4. Use the kinetic molecular theory of matter to explain your results of the

ethanol and warm ethanol samples.