Wood to Wheels- Inquiry Lesson Plan
Lesson Introduction
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Title:How can a solution of ethanol and water be separated?
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Subject/ target grade: 10
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Duration: 1 45 minute period
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Setting: science lab
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Learning Objectives: Student will be able to perform a distillation and separate water and
ethanol. They will be able to describe the process and how it occurs.
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Wisconsin Standards:
G.12.2 Design, build, evaluate, and revise models and explanations related to
the earth and space, life and environmental, and physical sciences
C.12.3 Evaluate* the data collected during an investigation*, critique the datacollection procedures and results, and suggest ways to make any needed
improvements
C.12.4 During investigations*, choose the best data-collection procedures and
materials available, use them competently, and calculate the degree of precision of the
resulting data
C.12.5 Use the explanations* and models* found in the earth and space, life and
environmental, and physical sciences to develop likely explanations* for the results of
their investigations*
C.12.6 Present the results of investigations* to groups concerned with the issues,
explaining* the meaning and implications of the results, and answering questions in
terms the audience can understand
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Lesson Overview: Students will perform a distillation using the products of their fermentation
reaction in the previous lesson. Students will produce a small amount of purified ethanol after
their distillation which can be burned in a watch glass or alcohol burner.
Lesson Core
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The Guiding Question: How can a solution of ethanol and water be separated?
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Materials and Equipment Needed:
Equipment
Distillation apparatus-glass elbow, condenser, glass beads. shaped flask, distillation
column,
Heating mantle or hot plate
Boiling chips
Graduated cylinder or other container for collection of ethanol
Rubber tubing
2 thermometers
2 ring stands with clamps
Reagents
Fermentation media from previous lab or solution of water and ethanol.
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Safety precautions: Appropriate lab attire, safety glasses, use caution with heating mantle or
hot plate, beware of hot glass, keep ethanol away from open flame(flammable).
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Advanced Preparation: See previous lab for fermentation of glucose to produce ethanol.
Distillation apparatus should be set up. Students will place their fermentation product into the
collective distillation pot.
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Background Information for Teachers: Distillation is a physical process to separate mixtures
which have different boiling points. The vapor of the ethanol will evaporate first. The
thermometer measuring the gas temperature should read 75-80oC when the ethanol is
evaporating. When the ethanol has completed its evaporation the water will start to boil at a
higher temperature and the temperature of the vapor will start to increase.
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Engage: How can we separate two liquids that are miscible? Where can we find the boiling
points of water and ethanol? How will we know what is boiling? Have students complete
research and write the boiling points of both ethanol and water in their lab journals. What is the
temperature of water and ethanol vapor? Write this in your lab journal. How does knowing the
boiling points help us?
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Building on prior knowledge: What are other ways that we have separated mixtures? What
makes separating a solution different? Why would we want to separate a solution?
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Pre-teaching: What were the products of your fermentation? Can the solution in your flask be
used as a fuel? Why or why not? How can we remove the ethanol from the water so it may be
used as a fuel?
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Explore:
1. Place fermentation media from lab the previous day into the distillation pot. Be careful not to
mix or swirl the flask before pouring it in so the cell mass remains at the bottom of the flask
and is not poured into the pot.
2. Place the pot on the heating mantle or got plate and turn heat up to the point of boiling.
Watch thermometers in the pot and vapor. When the thermometer measuring the vapor is
reading 75-80oC ethanol is being condensed in the condenser.
3. Make sure the is a graduated cylinder to catch condensate.
4. When temperature of the vapor starts to rise and exceeds 80oC remove the collection
container. After this point water will start being distilled and will dilute the ethanol in the
collection container.
5. Measure a small amount of the ethanol and calculate the density. Using the density curve
attached calculate the percent ethanol captured.
6. Have the teacher either burn the ethanol in a watch glass or alcohol burner. Make a note of
how much water is left behind when the sample is burned.
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Explain: Students should record their ethanol percent in their lab journals. Have students list
their ethanol percent on the board and record the percent from other groups into their lab
journals.
● Elaboration: Discuss with students: Why did some groups have a greater amount of ethanol in
their sample? How did measuring the density tell you the purity of the ethanol? Is their any way
that we could produce ethanol with a greater purity? What other applications of distillation are
used in every day production?
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Evaluate and Lesson Closure: Students will be evaluated based on their lab notebooks and
data and results.
Students should write a short paragraph in their lab journals discussing the process of
distillation. If we could increase the purity of ethanol would it run better in our engines?
How does all of this relate to alternative fuels and our lives? What research should be done to
help this problem?
Lesson Extension
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Additional Resources:
See picture of distillation apparatus used at MTU
JSA - distillation
http://swc2.hccs.edu/pahlavan/2423L7.pdf
http://awsnabeel.xanga.com/540284105/item/
http://www.chem.wisc.edu/courses/342/Fall2006/Experiment_2.pdf
Ethanol Data
Boiling point:
Density:
78.5°C
0.785 g ethanol / cm3 ethanol
Density of Ethanol – Water Mixtures at 25° C
Volume % of ethanol
Mass %
Density (g/ cm3)
0
10
0
7.98
1.00
0.9835
20
16.16
0.9717
30
24.54
0.9596
40
33.24
0.9448
50
42.37
0.9265
60
52.03
0.9053
70
62.34
0.8815
80
73.45
0.8551
90
100
85.65
100
0.8249
0.787
David R. Shonnard, Department of Chemical Engineering, Michigan Technological University