Summer Research Program for Science Teachers

Annelisse Falzone

The Bronx High School of Science

 

Action Plan

The synthesis of Some Organic Compounds and their Representative Structures

AIM:        How can we represent organic compounds in 3-dimensions?

Student Objectives:   

  1. In this experiment, students will synthesize acetic acid, ethyl ethanoate, and *ethanol (optional) [9-12 Content Standard B- Chemical reactions]
  2. Students will identify basic functional groups on organic compounds.
  3. Students will write synthesis reactions for all three reactions.
  4. Students will use molecular modeling sets for building 3-dimensional structures.
  5. Students will use hyperchemlite to build their 3-dimensional structures on a micro-computer and print out their structures. [Teaching Standard D- Make accessible technological resources]

     

Materials:      

Goggles and apron, balance, 3 to 5 pyrex test tubes (18 X 150mm), 1 pyrex test tube (13 X 100mm)

a test tube holder, utility clamp, ring stand, a Bunsen burner, iron ring, wire gauze, dropper pipette, litmus paper (blue), cotton, 2 beakers (50 and 100 ml), graduated cylinder 10 ml and 100 ml, an Erlenmeyer flask (250 ml), and distillation apparatus.

Discussion:     The instructor should review bonding, hybridization and functional groups.

[9-12 Content Standard B- Structure and properties of matter]

Synthesis of Acetic Acid:  

Place approximately 1 gram of   NaC2H3O2 into a large test tube.  Add 2 ml of 9.0 M H2SO4  CAUTION: H2SO4  causes severe burns; avoid skin contact.  Warm the solution over a Bunsen burner using a test tube holder and carefully note and describe the odor.  CAUTION: DO NOT POINT OPEN END OF TEST TUBE AT ANOTHER STUDENT OR YOURSELF.  Remove a few drops of solution and add to 2 ml of distilled water in a small test tube.  Observe its solubility and test with blue litmus paper.  Record your observations.  Note: Save some acid for the preparation of ethyl ethanoate.

Synthesis of Ethyl Ethanoate: 

To the acetic acid prepared previously add 2 ml of ethanol.  Caution:  Alcohols are toxic and flammable. Avoid skin contact and inhalation of vapors.  Keep away from flames.  Warm the solution in a beaker of boiling water for 2 or 3 minutes.   Pour the contents of the test tube into a small beaker note the odor.  Record observations.

Synthesis of enthanol and purification (optional): 

Place 50 ml of distilled water in a 250 ml Erlenmeyer flask, add
10 ml of molasses, and a few granules of yeast and stir.  Place a cotton plug in the mouth of the flask and set aside for 24-30 hours.  The solution will be converted into ethanol and carbon dioxide gas.

Optional/Teacher Demonstration:  Alcohols can be separated by distillation at a temperature slightly higher than its boiling point of 78 C.

Analysis:          1.     Synthesis of acetic acid, ethanol and ethanoate.
                        2.     Have students write out structural formulas for the acid, ester and alcohol.
                        3.     Using molecular modeling sets construct 3-dimensional structures.
                        4.     Using Hyperchemlite draw and print-out structures for al three products formed.

Questions:   1.    What familiar odor was associated with ethyl ethanotae?
                       2.     Acetic acid is soluble in water.  Explain.  Why?
                       3.     Explain how molecular modeling programs can be helpful to scientists.

[Teaching Standard B- Orchestrate scientific discourse]

 

 

Return to Chemistry Lesson Plans Menu