Organic Chemistry - Course Description
Monday, August 13, 2012
This block considers chemical aspects of some major life processes that occur in plants, animals and human beings. Themes that are explored through discussion, demonstrations and student experimentation include:
• Methods of chemistry as a laboratory science.
• How the chemistry of life processes was developed – history of science
• The balance inherent in chemical processes
• Practical applications of life chemistry
Our goal is to find out something about the chemistry of life- what chemical transformations can we attribute to life?
Initially, the block focuses on developing skills and background in chemistry and provides some opportunities to explore experimental methods. Subsequently, students are asked to observe or to execute experiments that demonstrate aspects of important life-related processes. We examine the nature of gases and their roles in chemical reactions, especially in combustion. We examine our dependence on fossil fuels and viable alternative energy sources. Experiments involving photosynthesis and respiration establish fundamental properties and the relationship between these two processes. Through experimentation with fermentation and distillation, an application in the field of biofuels is taken up.
Faculty: Jim Kotz, High School Science Teacher
Class Dates: April 29th - May 17th, 2013
Curriculum Area: Morning Lesson Block
Experiment 1 Properties of Gases (Rough form due Wednesday, May 1, 2013)
Outline:
Part 1: Carbon Dioxide
Describe the gas generator that was used to produce carbon dioxide. Include a detailed drawing. How was the gas collected?
Describe, in detail, the tests that were performed:
The flame test. Density test. Limewater tests (3 forms). Bromthymol blue tests (2 forms). What do we conclude about this gas from these tests (show in a chart). Where is carbon dioxide found in the human body and elsewhere?
Part 2: Oxygen
Describe the gas generator that was used to produce oxygen. How was the gas collected?
Describe, in detail, the tests that were performed:
The flame test. Density test. Limewater test. Bromthymol blue test. What do we conclude about this gas from these tests (show in the same chart).
Part 3: Hydrogen
Describe the gas generator that was used to produce hydrogen. How was the gas collected? (show in a drawing.)
Describe, in detail, the tests that were performed:
The flame test. Density test. Limewater test. Bromthymol blue test. What do we conclude about this gas from these tests (show in the same chart).
Discussion Outline: Experiment 2 Combustion of a Candle
In this experiment we showed how we can arrive at the following process description of the combustion of a candle:
Wax (fuel) + Oxygen --> Carbon Dioxide + Water + heat/light
We did at least one experiment for each term in the description to verify its presence.
How did we show that wax, which is a hydrocarbon, is the fuel?
How did we show what role the wick plays in a burning candle flame?
Oxygen is a necessary reactant (the “oxidizer”): Which experiments?
Carbon Dioxide is a product: Which experiment? (include sketch of set-up)
Water is a product: Which experiment?
How can you show that heat and light are products?
How did we show that there is at least one intermediate product in the burning of a candle?
(What is actually glowing in the brightest part of the flame?)
Include a sketch of a burning candle, labeled as done in class.
Experiment 3 Carbohydrates
Part 1 Describe the solubility of sugar, starch and cellulose (cotton) in water
Part 2 Describe the sensation of sugar, starch and cellulose (cotton) in your mouth
Part 3 Describe heating the three carbohydrates, paying attention to similarities and differences
Part 4 Describe Fehling's test when performed on glucose, fructose, maltose, sucrose and starch.
What additional steps are necessary to produce a positive result for sucrose and for starch? Explain results in terms of the structures of these substances.
Part 5 Discuss where carbohydrates are found in plants and their place in the life of a plant. Show this using a diagram. What aspects of our experiments are consistent with this picture?
Experiment 4 Carbon Dioxide and Light as Reactants in Photosynthesis
Procedure: Describe the intial modification of B-Blue using exhaled breath. What is the color change? (Why?)
What was added to one of the two test tubes in each pair, besides the modified B-Blue? Most of the pairs of test tubes were placed outside in sunlight, but one pair was kept in darkness.
Observations:
What were the results?
Conclusion: What have you learned about the process that took place this experiment? Be sure to say what in the experiment leads to your conclusion.
Experiment 5 Anaerobic Respiration (Rough copy due on Monday, May 13)
Part 1:Fermentation
Describe how we set up the flask with yeast, water and raisins. Once it was set up, we maintained the temperature at about 85deg. F. A balloon was attached to the top of the flask. What happened after awhile?
What test did we perform, investigating the identity of a gas?
Part 2 Distillation
Describe, in detail, the distillation set up.
The mash (from part 1) is heated. At approximately what temperature (in Deg. C) does the liquid begin to boil?
How does this compare with the boiling temperature of water?
Describe how the liquid extraction process works.
Part 3 Tests on the extracted liquid:
Boiling pt., appearance, cooling (thermometer and skin), taste sensation, burning, density
Conclusions:
What is the liquid (other than water) that is extracted?
Describe the process that is creating the two products that we found in this experiment. What is it called? Compare it with aerobic respiration.
Photosynthesis and Respiration
Respiration:
Give a process description of aerobic respiration.
(What experiment that we did relates to a product of this process?)
Give a process description of anaerobic respiration.
(Which of our experiments demonstrates this process?)
Photosynthesis:
Give a complete process description of photosynthesis.
How does it compare with aerobic respiration?
Describe our experiments (either that we did or that we discussed) that relate to the process description of photosynthesis.
Experiment 6 Esters
Describe how you made an ester by combining an alcohol and an organic acid. Which pair did you use?
What catalyst was used? What was the resulting smell?
(List all the possible alcohols and organic acids that were used.) Where are esters typically found in plants?
Indicate in a drawing how the densities of various plant-related substances compare (consider carbohydrates, alcohol, organic acids, esters)
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