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SCH4U
Investigation 1:
Physical and Chemical
Properties of Alcohols and Esters
Organic Chemistry
Introduction
Alcohols are common organic substances which undergo a variety of chemical reactions. The two
simplest alcohols, methanol and ethanol, are very important commercially. Methanol, CH3OH, also
known as wood alcohol, is toxic leading to blindness and death if swallowed. Methanol can be used as
a motor fuel, and it is the starting point for the manufacture of many other chemicals. Ethanol,
CH3CH2OH, is the alcohol found in alcoholic beverages. Contrary to popular belief, ethanol is a
depressant. Ethanol can also be used as a motor fuel and is often mixed with gasoline to form so
called gasohol.
Pre-lab
/7 [K/U]
/9[T/ I]
/3 [A]
/4 [C]
1. Compare an alcohol with similar compounds- for example, ethanol (CH3CH2OH),
methoxymethane and ethane . What should you expect for the relative values of melting point,
boiling point and solubility in water? Why? (3 T/I)
2. Compare the melting point, boiling point and solubility in water of a short chain length alcohol
like ethanol with a longer chain length alcohol like 1-heptanol. Explain your answer. (3 A)
3. What is the correct chemical equation for the reaction of 2-methyl-2-propanol and sodium? (2
T/I)
4. Write the chemical reactions for the syntheses of the two esters you will be performing in this lab.
Provide the full structural diagrams and names of the reactants and products in each of the
reactions. (6 K/U)
5. Why do you add sulfuric acid to the reactions in this lab? (1 K/U)
6. Create a flow chart in your lab notebook for this experiment (4 T/I)
7. Create two observation tables for this experiment in your notebook. (4 C)
SAFETY PRECAUTIONS
1. Wear your safety goggles.
2. Know the locations of the fire extinguisher, fire blanket and eye wash station.
3. WARNING: alcohols are volatile, flammable and toxic.
Part I: Reactions of Alcohols
Purpose: In this lab you will examine the solubility of alcohols in water and reactions of alcohols with
sodium.
MATERIALS
methanol
1- pentanol (amyl alcohol)
distilled water
400 mL beaker
6 stoppers
2-methyl propanol (isopropanol)
ethanol
pH paper
4 test tubes
test tube rack
1-butanol
Solubility in Water
a.
b.
c.
d.
Place 2-3 mL samples of each alcohol into separate, clean, labeled test tubes.
Add an equal quantity of distilled water to each test tube.
Stopper the test tubes and shake
Compare and record the relative solubility of each alcohol in water.
Reaction of Alcohols with Sodium (Demo only)
e. Place 5 mL samples of each alcohol into separate, clean, labeled test tubes.
f. Add one pellet to each test tube.
g. Compare and record the relative reactivity of each alcohol with sodium.
h. When the reactions are complete, add about 5 mL of distilled water to each test tube. Test the
resulting solution with pH paper and record the results
Part II Esters
Purpose: To study the preparation and properties of some ester compounds.
Materials
250 mL beaker
test tube rack
ethanol
glacial acetic acid
2- 50 mL beaker
Hot plate
2 test tubes
pipette or eye dropper
conc. sulfuric acid
methanol
Procedure
a. Place about 150 mL of water into the beaker. A hot plate to heat the water to boiling for
a water bath.
b. Place 5 drops of methanol into a test tube. Carefully add 5 drops of glacial acetic acid
and then 3 drops of concentrated sulfuric acid.
c. Place the test tube into the hot water bath for a few minutes. Remove from heat.
d. Pour about 10 mL of cold water into your test tube. Pour contents into a 50 mL beaker.
Record the smell of the ester formed. Compare to familiar odors (such as fruits and
flowers) - remember to waft the smell towards your nose with your hand.
e. Repeat steps b-d substituting ethanol for methanol.
Analysis Questions
1. Explain the difference in reactivity between sodium and short chain length alcohols like ethanol
and longer chain alcohols like 1-pentanol. (2 T/I)
2. The distinction between “natural” and “synthetic” products is usually based on the source of the
product, whether it is made by living organisms or by a laboratory procedure. In your opinion,
what criteria should be used to distinguish a “natural” product from a “synthetic” product? (3 A)
3. Write a general conclusion for this lab. (2 T/I)
4. Give two errors that may have occurred during your experiment. (2 T/I)
Marking scheme for lab:
10 marks inquiry: Lab performance (4 marks), Analysis questions 1, 3, 4 (2 marks each)
3 marks application: Analysis question 2
TOTAL
/13 marks