Date _______________ Hr ____ Name _________________________________________________
The Evaporation Rate of Propanone
Introduction: Propanone, or as it is more commonly called acetone, is a typical solvent.
A solvent (from the Latin solvō, “I loosen, untie, I solve”) is a substance that dissolves another
substance, resulting in a solution. A solvent is usually a liquid but can also be a solid or a gas.
The evaporation rate of a solvent is dependent upon temperature, hydrogen bonding, molecular
size and weight, heat of vaporization, specific heat, vapor pressure, humidity, air movement and
other properties and conditions.
Purpose: The goal of Part 1 of this lab is to measure the rate that acetone evaporates and
determine if a relationship exists between mass evaporated and time. In Part 2 a second
relationship between evaporation rate and surface area of liquid (a function of the size of
container) will be explored.
Hypothesis: If ______________________________________ then _______________________________________________
(action)
(effect)
Experimental design: Independent variable: ________________ Dependent variable: ________________
1
Constants (list at least 3 variables that should 2
Part 1
not be allowed to change)
3
Procedure
1. Measure approximately 5 mL of acetone with a small grad cylinder.
2. Place the acetone in a clean dry beaker.
3. Record the mass of the beaker and acetone every two minutes for 20 minutes.
4. Record the diameter of the beaker used.
Data Beaker size (read label) ____________ Beaker Diameter (record number) _____________
Mass Measurements
Time
Mass
(min)
(g)
0
2
4
6
8
10
12
14
16
18
20
Calculations
Mass
(mg)
2 min evap.
change (mg)
XXXXXXXXXXXXX
Total evap.
change (mg)
XXXXXXXXXXXXX
Data Analysis - Graphing
1. Plot a graph of your data. The Y-axis should be total change (loss of mass in milligrams; the Xaxis should be time in minutes. Draw the best-fit straight line in pencil. Include a title and label
each axis.
Data Analysis - Calculations
2. From the graph determine the evaporation rate in mg / min. (Slope = _____________ mg/min)
Do the work on the graph as instructed by your teacher.
3. Does the acetone evaporate at a constant rate? ______________
Does the graph show a relationship between mass evaporated and time? __________________
What type of relationship does the graph show? __________________________
Part 2
1. Calculate the surface area of the acetone in square centimeters. (Area of a circle = ____________)
2. Calculate the evaporation rate in mg / min / cm2. (Slope/area)
3. Calculate the grams of acetone used. You cannot find the mass of the acetone by subtracting
the empty container from the full container. You can find the mass if you use the 5 mL volume
and the density of acetone (0.791 g/mL).
Questions - Use your text or other references to answer these questions.
4. What is the formula (ie. formula for water is H2O) for acetone?
5. List 3 uses for acetone.
6. What is the boiling point of acetone in ˚C, ˚F, and K?
7. Use the K-P model to describe what is happening, at the particle level, as the acetone
evaporates. Why is this happening, where does the energy come from?
8. What effect would increasing the pressure (at constant temp.) in the room have on the
evaporation rate?
Group
Initials
Beaker
Volume (mL)
20
20
30
30
50
50
100
100
150
150
250
250
Diameter (cm)
Evaporation
Rate
mg/min.
mg/min per
cm2