Embedded Files
Lesson Instructions
Lesson Instructions
Review the learning goals and success criteria for Topic 1: 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
Learning Goals
I am learning to ...
Draw structural isomers for a hydrocarbon.
Name and draw branched and cyclic alkanes.
Name and draw alkyl halides.
Minds On
Minds On
What is Organic Chemistry?
What is Organic Chemistry?
Organic chemistry is the study of carbon compounds. An organic compound is a molecular compound containing carbon with the exception of carbon monoxide, carbon dioxide, and hydrogen cyanide.
Since carbon has 4 valence electrons, its atoms tend to form 4 covalent bonds. Carbon atoms have the unique ability of bonding with one another to form chains. These chains become the backbones for a range of molecules, some of which are very complex.
Example - Polyethylene
Example - Polyethylene
Many of the plastics that we encounter every day, including plastic bags and bottles, are made from polyethylene, an organic compound composed of long chains of carbon and hydrogen atoms. In this unit we will learn about organic compounds, including their structure, function, and the positive and negative impacts that these molecules can have on the world around us.
Figure 1. An example of a common organic compound, polyethylene. This compound is used in the creation of plastics.
What are some characteristics of carbon?
What are some characteristics of carbon?
The prevalence of carbon in organic molecules can be attributed to several factors, including:
CARBON'S ABILITY TO BOND TO ITSELF
CARBON'S ABILITY TO BOND TO ITSELF
Carbon is capable of making bonds with other carbon atoms to form chain-like structures. These carbon chains are the basis of many biological molecules, including nucleic acids, proteins and lipids.
CARBON CAN FORM MULTIPLE BONDS
CARBON CAN FORM MULTIPLE BONDS
Carbon can form stable single, double, and triple bonds with other carbon atoms allowing the generation of large and complex molecules. These bonds are incredibly strong, making carbon-carbon chains important as backbones for organic molecules.
CARBON HAS A HIGH BONDING CAPACITY
CARBON HAS A HIGH BONDING CAPACITY
Carbon is one of only a handful of elements capable of forming four bonds, allowing carbon to bond with a variety of other elements to create complex structures. While silicon, also in group 14, is equally able to make four bonds, the bond strength is less than what we see between carbon and other atoms.
You can review properties of elements, including the Group 14 elements, by clicking on the interactive periodic table below.
Action
Action
What is a hydrocarbon?
What is a hydrocarbon?
A hydrocarbon is a compound composed only of carbon and hydrogen.
What is an alkane?
What is an alkane?
An alkane is a hydrocarbon made up of only carbon-carbon single bonds.
Figure 2. Examples of three alkane hydrocarbons. From left to right: methane, ethane, and propane.
Alkanes are saturated hydrocarbons
They consist of a carbon atom bonded to a maximum number of hydrogen atoms.
Alkanes have the chemical formula CnH2n+2.
Structural Diagrams
Structural Diagrams
Complete Structural Diagrams
Complete Structural Diagrams
Shows all of the atoms in a structure and the way they are bonded to one another.
Figure 3. An example of a hydrocarbon drawn showing its complete structure.
Condensed Structural Diagrams
Condensed Structural Diagrams
Shows the bonds between the carbon atoms but not those between the carbon and hydrogen atoms.
Figure 4. This is the same alkane from Figure 3, drawn in the condensed form.
Line Structural Diagrams
Line Structural Diagrams
Shows only lines representing bonds between carbon atoms.
Figure 5. This is the same alkane from Figure 3 and 4, drawn as a line diagram.
Rules for Naming Alkanes
Rules for Naming Alkanes
These are the naming and drawing rules from your textbook.
Below are Mr. C's Simplified Naming Rules.
Below are Mr. C's Simplified Naming Rules.
(1) Find the longest carbon chain, this is the parent chain.
(2) Number the carbons such that the branches are on the lowest position #.
(3) Name the alkyl branches in alphabetical order, including a number to indicate position.
(4) If there is more than one of the same branch, use a prefix to indicate this (di, tri, tetra, etc.).
(5) Separate #s and letters with a hyphen, separate #s with a comma.
Alkane Parent Chain Names
Alkane Parent Chain Names
You will need to memorize the first two columns of this table. The molecular formula can be easily calculated by memorizing the formula for alkanes, CnH2n+2.
Alkyl Groups
Alkyl Groups
Example 1 - Name the following compounds.
Example 1 - Name the following compounds.
Figure 7. 4-ethyl-3-methylheptane.
Figure 8. 3-ethyl-2,4-dimethylhexane.
Figure 9. This compound can be named as:3,6-dimethyl-4-propan-2-yloctane, or3,6-dimethyl-4-isopropyloctane.
Figure 10. 3-ethyl-5-methylheptane.
Example 2 - Draw the condensed structural diagram for 3-ethyl-2,2-dimethylhexane
Example 2 - Draw the condensed structural diagram for 3-ethyl-2,2-dimethylhexane
Example 3 - Draw the line diagram for 6-ethyl-2,5-dimethyl-4-propylnonane
Example 3 - Draw the line diagram for 6-ethyl-2,5-dimethyl-4-propylnonane
Structural Isomers
Structural Isomers
Structural isomers are compounds that have the same molecular formula, but different structures.
They have a different shape and bonding, therefore, different properties.
Figure 11. In pentane, the terminal (circled) CH3 and the hydrogen (also circled) switch places. There is no loss of carbon or hydrogen to the overall chemical formula. However, the new position of these carbons and hydrogens creates a totally different structure, with a different name. The CH3 becomes a side chain (alkyl group) on a now shorter parent chain called butane. Thus, the new name of this compound is2-methylbutane.
Most hydrocarbons with 4 or more carbon atoms exhibit structural isomerism. Structural isomerism occurs when two molecules each have the same numbers and types of atoms but these atoms are bonded in different ways.
Each molecule is a structural isomer of the other. For example, there are to alkanes that have the same molecular formula C4H10 (Figure 12). Butane is a straight-chain molecule, while methylpropane has a branched structure. Both have the same formula, but because of their different structures, these compounds exhibit different properties. For example, the boiling point of butane is -0.5 oC, whereas that of methylpropane is -12 oC.
Figure 12. (a) Butane (b) The branched isomer of butane: methylpropane.
Example 4 - Name and draw all the structural isomers for C6H14.
Example 4 - Name and draw all the structural isomers for C6H14.
Cycloalkanes
Cycloalkanes
Cycloalkanes are regular alkanes that form a ring or loop.
NAMING CYCLOALKANES
NAMING CYCLOALKANES
The cyclic structure is always the parent chain, and has the prefix “cyclo”.
Number the carbons, in either direction, so that the branches have the lowest possible position number
When drawing, always use a line diagram for the cyclic chain.
Example 5 - Name the following cyclic alkane.
Example 5 - Name the following cyclic alkane.
Figure 14. 1-ethyl-2,4-dimethylcyclohexane
Example 6 - Draw a structural diagram for the following ...
Example 6 - Draw a structural diagram for the following ...
1-ethyl-2,4-dimethylcyclopentane
1-ethyl-2,4-dimethylcyclopentane
Haloalkanes
Haloalkanes
Haloalkanes are compounds that exist when one or more hydrogen atoms have been substituted with halogen atoms (F, Cl, Br, I - refer to periodic table at the top of this page).
NAMING HALOALKANES
NAMING HALOALKANES
Name using a prefix (fluoro-, chloro-, bromo- or iodo-).
List in alphabetical order and include a position # (alkyl groups have equal priority to halide groups).
Halides are listed alphabetically with alkyl groups.
Example 7 - Name the following haloalkane.
Example 7 - Name the following haloalkane.
Figure 15. 2-bromo-3-chloro-4-methylpentane
Consolidation
Consolidation
Try to name or draw the following hydrocarbons. Once you've attempted them, you can click to see the correct answer!
The following resources are NOT required. However, they are available for extra practice.
Additional Practice Questions - from Michigan State University
Additional Practice Questions - from Michigan State University
Additional Practice Questions - from Grossmont College, California
Additional Practice Questions - from Grossmont College, California
Additional Practice Questions - from Science Geek AP Interactive Chemistry Review Activities
Additional Practice Questions - from Science Geek AP Interactive Chemistry Review Activities
This lesson is now complete. Consolidate your learning by evaluating the self-check below and the assigned practice questions.
Self-Check
(This is a self-assessment of your learning – you do not need to submit this).Self-Check
How prepared am I to start my homework? Can I ...
draw structural isomers for a hydrocarbon
name and draw branched and cyclic alkanes
name and draw alkyl halides
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