Unit 3, Topic 1:

Organic Compounds and Alkanes

Lesson Instructions

Review the learning goals and success criteria for Topic 1: Organic Compounds and Alkanes.
- Review the minds on, action, and consolidation sections of the lesson, completing any tasks as outlined.
- Complete the fill-in-the-blanks handouts that have been provided to you. They have been linked below.
- Practice and apply what you've learned by completing the practice tasks outlined at the end of the lesson.

Learning Goals

I am learning to ...

- Identify, name and draw alkanes.
- Describe the term “organic” as it relates to chemistry.
- Name and write formulas for alkanes.

Minds-On

Action

Organic Compounds

Compounds that contain carbon (does not include CO_(g), CO_{2 (g)} or ionic compounds with carbon). They also include hydrogen (see hydrocarbon below) and sometimes oxygen or nitrogen.

Hydrocarbons

Organic compounds that contain carbon and hydrogen atoms in their molecular structure.

EXAMPLES OF ORGANIC MATTER AND MATERIALS

- Examples of organic compounds are sugar, carbohydrates, fats, proteins, cotton, silk, propane, methane, and fossil fuels.
- Carbon and hydrogen account for 90% of all biological matter.

REPRESENTING HYDROCARBON COMPOUNDS

Carbon has 3 main properties that allow for so many different compounds to form.

1. Carbon has four valence electrons.

- This allows it to form 4 covalent bonds (either with itself or with other atoms such as H, O, or N).

2. Carbon can form strong bonds with itself.

- Single, double or triple bonds. The resulting compounds are generally stable. Very few other atoms can do this.

3. Carbon atoms can bond to form a variety of geometrical structures.

- Straight chains, branched chains, rings, sheets, tubes and spheres. No other atom can do this.

Watch the following videos the properties of carbon and bond formation.

STRUCTURAL DIAGRAMS

There are three different ways to represent organic molecules.

Structural Diagrams
- Shows all the atoms in a structure and the way they are bonded to one another.
Condensed Structural Diagrams
- Shows the bonds between the carbon atoms, but not those between the carbon and hydrogen atoms.
Line Structural Diagrams
- Shows only lines representing the bonds that exist between carbon atoms. It gives us a better sense of the 3-D shapes of the molecules.

ALKANES

Alkanes are hydrocarbons that are joined by single bonds. [ending: -ane]

We will be learning about alkanes that include one (1) to ten (10) carbons. The number of carbons in an alkane determines the name of that particular molecular.

STRAIGHT CHAIN ALKANES

Draw the structural diagram and line diagram for each of the straight chain alkanes.

The answers for this chart are found here:

ALKYL BRANCHES

Smaller branche form off of the parent chains listed above. We call these alkyl branches. Alkyl branches will always be shorter than the parent chain. The parent chain is the longest chain in the molecule. Below are the alkyl branches you will need to recognize. [ending: -yl]

RULES FOR NAMING ALKANES

Find the longest carbon chain, called the parent chain.
Number the carbons of the parent chain so that the alkyl branches are on the lowest position number.
If there is more than one of the same alkyl branch, use a prefix to indicate this (di, tri, tetra, etc.).
Write branches in alphabetical order (ignoring prefixes), including a number to indicate position.
Separate #’s and letters with a hyphen, separate #’s with a comma.

“If there is more than one of the same alkyl branch, use a prefix to indicate this (di, tri, tetra, etc.).”

Here is an example of what that means.

Practice Naming Alkanes

Example 1. Name the following compound.

Example 2. Name the following compound.

Example 3. Name the following compound.

Example 4. Name the following compound.

Practice Drawing Alkanes

Example 5. Draw the following compound.

3-ethyl-2,2-dimethylhexane

Example 6. Draw the following compound.

6-ethyl-2,5-dimethyloctane

Consolidation

- To practice your skills, draw or name the following alkanes. When you are done, you can check your answers. Then, scan and submit your consolidation work on D2L.

Draw the following compounds.

- 3-ethyl-2-methylpentane (Show Answer)
- 2,3-dimethylpentane (Show Answer)
- butane (Show Answer)
- 2-methylpropane (Show Answer)

Name the following compounds.

(Show Answer)

This lesson is now complete. Return to D2L - Brightspace and complete the assigned tasks to consolidate your learning.

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