North Lake College Saponification of Fatty Acids Chemistry Worksheet

CHEMISTRYSaponification of Fatty Acids
Investigation
Manual
SAPONIFICATION OF FATTY ACIDS
Table of Contents
2
Overview
2
Outcomes
2
Time Requirements
3
Background
5
Materials
6
Safety
6
Preparation
6
Activity 1
7
Activity 2
8
Disposal and Cleanup
Overview
This investigation will provide students the opportunity to prepare
soap through a saponification reaction. The physical and chemical
properties of manufactured soap will also be tested. This investigation will require at least 72 hours to complete.
Outcomes
• Identify the steps involved in producing soap.
• Determine the characteristics of the soap produced in this
investigation.
• Describe the chemical nature of soap.
Time Requirements
Preparation ……………………………………………………………. 5 minutes
Activity 1: Soap Preparation ……………………. 45 minutes + 72 hours
Activity 2: Properties of Soap ………………………………….. 45 minutes
Key
Personal protective
equipment
(PPE)
goggles gloves apron
follow
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Background
Soap production has been a part of human
culture for thousands of years, dating at least as
far back as 2800 BCE in Babylon. Typical recipes
consisted of animal fats and potash (a name
referring to the residue of a fire below a cooking
pot), which is the ashes of burned vegetation,
most commonly trees. Potash contains large
quantities of sodium hydroxide, which, when
added to animal fat, results in saponification.
(or another strong base) to a fat (triglyceride)
produces glycerol and soap molecules, which
are the salts of the fatty acids cleaved from the
glycerol molecule (Figure 2).
Figure 1.
The process of saponification occurs in equilibrium. The traditional soap-making process
utilizes a high concentration (more than 6 Molar)
of sodium hydroxide. The high concentration
of hydroxide ion (OH− ) helps push the reaction
toward completion, the right-hand side of the
reaction shown in Figure 2. Generally, heat is
applied to the reaction to promote rapid soap
formation. The high concentration of base and
high heat required in the “hot process” makes it
unsuitable as an in-home activity.
Figure 1 shows an example of a triglyceride
(fat) composed of the fatty acids, the tails of this
molecule, palmitic acid (top), lauric acid (middle),
and myristic acid (bottom).
In Activity 1, soap will be created through a cold
process. In the cold process, heat is required
only for melting the fat used (if it is solid at room
temperature). The vegetable oil that will be used
in Activity 1 is liquid at room temperature, so
heat is not required. A lower concentration (1 M
instead of 6+ M) of sodium hydroxide will be
used in order to limit exposure to corrosive
materials. This substitution will result in a soap
that is less solid than a traditional bar soap. The
sodium hydroxide and oil will be mixed in a vial
Saponification is a type of base hydrolysis reaction whereby the addition of sodium hydroxide
Figure 2.
continued on next page
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SAPONIFICATION OF FATTY ACIDS
Background continued
to allow for thorough mixing of the chemicals.
Without mixing, the aqueous sodium hydroxide
and the oil would separate into two layers. With
thorough mixing, an emulsion is formed. In an
emulsion, microscopic droplets of oil are
suspended in the water, allowing for a greater
surface area upon which the sodium hydroxide
and oil can react.
After 72 hours, the soap solution can be rinsed
with sodium chloride solution in a process
referred to as “salting out” the soap. The addition of sodium chloride helps the soap molecules separate from the water and allows for
easier filtering at the end of Activity 1.
Figure 3.
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Activity 2 will focus on the properties of soaps.
Soaps have several properties that affect their
use. For example, the pH of a soap is important,
as a high pH will make the soap corrosive and
cause severe irritation when used on the skin.
Soaps with a pH between 7 and 9 are generally
considered safe for use on skin.
Soaps are most effective at removing oil or
grease. The long nonpolar tails of soap molecules interact with the fats and oils to be
removed. The polar heads of the soap molecules are attracted to the water used for rinsing.
The soap molecules surround the drop of oil,
creating a bubble of soap called a micelle
(Figure 3), which can be rinsed away with water.
In hard water (water containing high concentrations of calcium or magnesium ions), soap
becomes less effective. The calcium and
magnesium ions react with the soap,
displacing the sodium ions and
forming an insoluble solid, most
commonly referred to as soap
scum. More soap is required to
produce a foamy lather with hard
water, as the soap reacts first
with the calcium and magnesium ions.
Materials
Needed from the equipment kit:
Included in the materials kit:
Sodium hydroxide, Vial, screw
1 M, 20 mL
cap, 2 dram
2 Test tubes
Beaker, 100 mL
Graduated
Graduated
cylinder, 50 mL cylinder, 10 mL
Vegetable cooking Glass
stirring rod
oil, 30 mL
Hard water
mix, 1 g
Scale
Sodium chloride,
saturated, 7 mL
Plastic funnel Filter paper
Weigh boat
Plastic spoon
Reorder Information:
Replacement supplies
for the Saponification of
Fatty Acids investigation can be ordered from
Carolina Biological Supply
Company, kit 580358.
2 Plastic
pipets
Call 800-334-5551 to
order.
Needed but not supplied:
• Camera or camera phone for photographs
• Water (bottled or purified)
• Household soap sample (optional)
pH paper packet
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ACTIVITY
Safety
Wear your safety
goggles, chemical
apron, and gloves at all times while conducting
this investigation.
ACTIVITY 1
A Soap Preparation
Perform this activity at least 72 hours before
performing Activity 2.
Read all of the instructions for this laboratory
activity before beginning. Follow the instructions closely and observe established laboratory
safety practices, including the use of appropriate personal protective equipment (PPE) as
described in the Safety and Procedure sections.
1. Place the empty dram vial and cap on the
balance and tare the balance.
Sodium hydroxide is corrosive. In the
event of contact with skin or eyes, the
affected area should be immediately
rinsed with water for 15 minutes.
4. Pour the sodium hydroxide into the dram
vial and secure the cap tightly. There should
be two distinct layers: the oil layer and the
sodium hydroxide layer.
Do not eat, drink, or chew gum while performing
this activity. Wash your hands with soap and
water before and after performing the activity.
Clean the work area with soap and water after
completing the investigation. Keep pets and
children away from lab materials and equipment.
5. Shake the dram vial vigorously until an
emulsion is formed and there are no distinct
layers visible, this can take 5 to 10 minutes.
Preparation
1. Read through the entire laboratory.
2. Gather all required materials.
3. Clear a designated lab area.
2. Using a pipet, dispense about 2 g of
vegetable oil into the vial.
3. In the 10-mL graduated cylinder, measure
2 mL of the 1 M sodium hydroxide.
6. Allow the mixture to stand for 10 minutes,
then shake the vial again until there are no
distinct layers.
7. Place the vial in a secure location and
allow the reaction to proceed for at least
72 hours. The vial can sit indefinitely until
time allows for the completion of the
activity.
8. After 72 hours, a solid will have formed at
the interface between the oil and sodium
hydroxide layers.
9. Place the plastic funnel (stem down) into the
100-mL beaker.
10. Fold the filter paper as shown in Figure 4,
and place it into the funnel.
11. Pour the solution from the vial onto the filter
paper in the funnel.
continued on next page
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ACTIVITY 2
Figure 4.
A Properties of Soap
1. Scrape the soap from the filter paper with a
spoon and weigh 0.5 g of soap and place it
into the 100-mL beaker.
2. Measure 50 mL of purified water with the
50-mL graduated cylinder.
3. Add the purified water to the 100-mL beaker.
12. With the 10-mL graduated cylinder, measure
2 mL of 25% sodium chloride solution.
13. Pour the sodium chloride solution into the
vial, cap the vial, and shake vigorously.
14. Uncap the vial and pour the solution onto
the filter paper in the funnel.
15. Add an additional 2 mL of 25% sodium
chloride to the vial, shake, and pour onto the
filter paper.
16. Remove the filter paper with the soap from
the funnel and place it on several paper
towels until Activity 2 is to be performed.
Preferably, let it rest overnight.
4. With the grease pencil, label the test tubes as
#1 and #2.
5. With a 10-mL graduated cylinder, measure
5 mL of soap solution into each test tube and
place them in the test tube rack.
6. Take the glass stirring rod and dip it into the
solution in test tube #1, then touch the stirring
rod to a piece of pH paper. Compare the color
to the pH chart and record the pH in the Data
Table.
7. Place your gloved thumb on top of test tube
#1; make sure your thumb has made a good
seal with the vial, and shake vigorously for 10
seconds.
continued on next page
Data Table.
Prepared Soap Sample
Household Soap Sample
pH of sample
Initial observation of foam layer
Oil test observation
Hard water test observation
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ACTIVITY
ACTIVITY 2 continued
8.
Take a photo of the foam layer
produced.
9. With a pipet, add 2 drops of vegetable oil to
test tube #1, cover the opening with a gloved
thumb, and shake for 10 seconds.
10.
Take a photo of the foam layer
produced.
11. Open the hard water mix packet and pour
the mix into the 50-mL graduated cylinder.
12. Fill the 50-mL graduated cylinder with
purified water to the 50-mL mark. Pour the
contents of the cylinder into the beaker.
13. Stir carefully with the glass stirring rod.
14. With a plastic pipet, dispense 20 drops of
hard water solution into test tube #2.
15. Using your gloved thumb to create a seal
with test tube #2, shake for 10 seconds.
16.
Take a photo of the foam layer
produced.
17. Thoroughly rinse the graduated cylinder,
beaker, test tubes, and pipets with water.
18. Optional: Repeat Activity 2 using a 1-g
sample of the household soap in step 1.
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Disposal and Cleanup
1. Dispose of solutions down the drain with the
water running. Allow the faucet to run a few
minutes to dilute the solutions.
2. Rinse and dry the lab equipment and return
the materials to your equipment kit.
3. Sanitize the workspace.
NOTES
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NOTES
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CHEMISTRY
Saponification of Fatty Acids
Investigation Manual
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Chemistry 1406 – Introductory to Chemistry I – Allied Health
Objective:
The purpose of this assignment is to help chemistry students use their scientific understanding and research to
understand public issues that relate to chemistry.
Signature Assignment: Medicinal Use of Marijuana
Medicinal use of marijuana to treat conditions such as cancer, HIV, neurological disorders, inflammatory pain and autoimmune
diseases has sparked numerous debates amongst therapeutic users and those who believe it should not be used medicinally.
Marijuana is currently classified as a Class I controlled substance by the federal government. As of 2019, 33 states, the District
of Columbia Guam and Puerto Rico have legalized the use of medical marijuana with each state requiring users to register but
also deciding on the amounts an individual is allowed.
Write a 4 page minimum paper discussing the benefits and challenges faced when using Marijuana medicinally. You may use
peer-reviewed research papers, academic journals, government sources such as science.gov, textbooks and other reliable
resources.
Your paper must include the following as stated in the grading rubric (attached separately):
1. Image – Select or draw an image that is properly referenced in your paper to show that you are able to relate
your image to your content. The selected image must help the reader understand the topic better.
2. Graph – You may plot a graph from a data table from your cited source or use a graph already drawn to show
that you are able to interpret the data table or graph. From the graph, what generalization can be made?
3. Mathematical Equations/ Calculations- Use relevant mathematical formulas used in chemistry to calculate an
unknown quantity in your paper such as molarity, charge, energy, calories, frequency, mass, slope, y-intercept
etc. In doing so you will demonstrate an ability to reason quantitatively.
4. Be sure to thoroughly discuss both sides of the issue and present your position. Presenting both sides of the
issue before you state your position demonstrates that you have critically analyzed the data and made a wellinformed decision.
5. Write your paper third person even as you write your position. Use proper grammar and punctuation.
6. Include in-text citations and cite sources on the last page. The APA 6th edition guide has been provided below
with examples to help you properly format your paper.
APA 6th Edition
•
Your essay should be a minimum of 1000 words typed and double-spaced on standard-sized paper (8.5″ x 11″),
with 1″ margins on all sides (top, bottom left and right margins)
•
APA recommends Times New Roman font size 12 pt.
•
Your essay should include four major sections: Title Page, Main Body, and References.
Title Page
•
Title of the paper, (12 words or less, use upper and lower case letter)
•
Include a page header (also known as the “running head”) at the top of every page and insert page numbers
flush top right. Type “SHORT VERSION OF YOUR TITLE” in the header flush left using all capital letters.
The running head is a shortened version of your paper’s title and cannot exceed 50 characters including
spacing and punctuation.
•
The words Running Head should only appear on the title page not the other pages, other pages should only
have SHORT VERSION OF TITLE.
•
the author’s name, (your name)
•
and the institutional affiliation. (Cedar Valley College)
•
Title Page should look like the example shown below:
References: How to Cite in APA example:
Contributors’ names (Last edited date). Title of resource. Retrieved from http://Web address for OWL resource
Paiz, J., Angeli, E., Wagner, J., Lawrick, E., Moore, K., Anderson, M.,…Keck, R. (2010, May 5). General format.
Retrieved from Online Weblink for APA Resource
APA Style 6th Edition YouTube link : Video Resource for Assistance in Using APA Standards