2 - Alkanes SCH4U Organic Chemistry

0c9282730ea80fe831cdaef1872dec31.doc SCH4U – Organic Chemistry

Date: ______Alkanes

The most basic form of ______Only ______and ______Used to form more complex organic molecules No points of ______Maximum number of hydrogens per carbon Contain only ______

Naming Alkanes Use IUPAC System ______Find the longest continuous chain of ______atoms and use that as the base name All end with “______” Base Names

CH4 ______C6H14 ______

C2H6 ______C7H16 ______

C3H8 ______C8H18 ______

C4H10 ______C9H20 ______

C5H12 ______C10H22 ______Drawing Hydrocarbons We don’t want to have to draw out everything in full We want to take shortcuts We create ______We group hydrogens to the ______atoms

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We also have ______A line is assumed to have a ______at the end if no letter is placed at the end of the line If not letters are present in a line, all junctions/corners are assumed to have ______Examples:

Isomers These are molecules with the same ______formula, but different ______formula

Both these molecules are C4H10

Draw the 5 isomers with 6 carbons

Branched Hydrocarbons Sometimes there are branches off of the main hydrocarbon chain We need to name each chain separately

Start with the longest continuous chain of carbon Count the number of carbons in the branch Use commas to separate numbers Use dashes to separate numbers and words

Examples:

Start with the longest continuous chain of carbon Number the carbons so that the branching gets the lowest numbers possible

If there are multiple branches, name them alphabetically If there are more than one of a given branch, you can use your prefixes to tell us how many

Cyclic Hydrocarbons Sometimes the longer chains can form ring structures We call this group of alkanes ______

To name this structure, count the number of carbons like before We use the prefix “______” to tell us it is a cyclic hydrocarbon

Homework Page 15 Questions 1-2