Optional: Organic Chemistry

Unit Overview

This unit is designed to present students with a broad understanding of organic chemistry. The nomenclature of organic chemistry was introduced in the unit Molecules and Compounds.

Here the concepts of functional groups, the importance of structure and the variety of organic compounds and reactions are stressed.

Factors of scientific literacy which should be emphasized

• A3 ..........holistic
• A4 ..........replicable
• A9 ..........human/culture related

• B4 ..........organism
• B16 ..........system

• C1 ..........classifying
• C4 ..........working cooperatively
• C6 ..........questioning
• C8 ..........hypothesizing
• C9 ..........inferring
• C12 ..........interpreting data
• C13 ..........formulating models
• C14 ..........problem solving
• C15 ..........analyzing
• C20 ..........defining operationally

• D1 ..........science and technology
• D4 ..........science, technology, and the environment
• D6 ..........resources for science and technology
• D8 ..........variable positions
• D9 ..........social influence on science and technology
• D10 ..........technology controlled by society

• E4 ..........using audio visual aids
• E5 ..........computer interaction

• F5 ..........respect for logic
• F6 ..........consideration of consequence

• G1 ..........interest
• G2 ..........confidence
• G3 ..........continuous learner

Foundational Objectives for Chemistry and the Common Essential Learnings

Consider the characteristics of organic substances.

• Recognize the difference between organic and inorganic substances.
• Name aliphatic or aromatic hydrocarbons using the IUPAC system.
• Distinguish between saturated and unsaturated compounds.
• Compare straight-chain, branched-chain, and cyclic organic molecules.
• Draw structural formulas for hydrocarbons.
• Identify important properties of different types of hydrocarbons.
• Identify some important uses of organic substances.
• Classify organic compounds based on their functional groups.

Develop intuitive, imaginative thought and the ability to evaluate ideas and processes. (CCT)

• Explore the rules which underlie the categories of organic compounds.
• Explore relationships and patterns.
• Design and construct models which illustrate principles and functions.

Suggested activities and ideas for research projects

• To 500 mL of skim milk, add 25 mL of vinegar. Heat the mixture gently while stirring continually. When the milk has curdled, remove from the heat and let the mixture settle. Decant the liquid from the mixture, being careful not to lose any solid. This mixture can also be strained through a coarse cloth, such as cheese cloth? (Why might that type of cloth be called cheesecloth?) Dry the solid.

  Add the solid to about 25 mL water, add about 5 grams of sodium carbonate (washing soda) or sodium bicarbonate (baking soda) and stir to make a paste. Add more water if necessary to make a smooth paste. The paste is a glue called casein glue. Devise some tests to compare its strength to the strength of other glues.

  Why is casein glue called an organic glue? What substances are found in the curds of milk?

• Many organic (carboxylic) acids will react with alcohols to form esters with strong aromas. Mix 1 mL acid with 1 mL alcohol in a 13x100 mm test tube. Add about 10 drops of concentrated H₂SO₄. Heat in a water bath (at about 80°C) for about five minutes. This will produce enough ester to be perceptible to most peoples' sense of smell. If not, pour the reaction mixture into a 250 mL beaker containing about 100 mL of water at about 50°. This should volatize the products.

  Try mixtures of glacial acetic acid and n-pentanol, glacial acetic acid and n-octanol, butanoic acid and butanol, and salycylic acid and methanol.

  Challenge question: What is the purpose of the H₂SO₄?

• Investigate the structures of various complex organic compounds. How are saccharin and sucrose similar? Why are dioxins produced as byproducts during the production or low-temperature combustion of PCBs? How do the structures of natural and synthetic estrogen compare?

Sample ideas for evaluation and for encouraging thinking

• What is the difference between an alkane and an alkene? How is this difference related to the difference between saturated fats, unsaturated fats, and polyunsaturated fats?

• Why are carbon containing compounds called organic compounds? CO₂ is most often classified as an inorganic chemical. What does being classified as an inorganic chemical mean? Construct an arguement for the case that CO₂ should be considered as an organic chemical.

• Alkanes with from one to four carbon atoms per molecule are gases at room temperature. Alkanes with more than four carbon atoms per molecule are liquids or solids at room temperature. Why?

• One process in the refining of crude oil involves the catalytic cracking of long chain carbon molecules to form short chain carbon molecules. Why is this done? What catalysts are used?

• Why is ethene (ethylene) such a useful chemical?