Hydrocarbons Ms. Richardson SCH3u/4c

Organic Chemistry Organic chemistry centers around the element carbon. Hydrocarbons are compounds made of the elements hydrogen and carbon. Hydrocarbons are the foundation of organic chemistry

Why is carbon so special? Carbon is unique as it is a group 14 element that can form up to four covalent bonds per carbon atom. Methane is the simplest of hydrocarbons.

Hydrocarbons Hydrocarbons are classified by the types of bonds contained within the compound. There are four major groups of hydrocarbons that we will study: Alkanes Alkenes Alkynes Aromatics

Alkanes Alkanes are the simplest group of hydrocarbons. They contain only single bonds, and are said to be saturated General formula: CnH2n+2 (where n is the number of carbons)

Representing Alkanes Structural formula: shows how the atoms are bonded together Condensed structural formula: omits the bonds between C and H Bond-line structure: a zig-zag formation showing only the bonds, where each point represents a carbon atom CH3-CH2-CH3

Naming Straight-Chained Alkanes # of C atoms Prefix 1 Meth- 2 Eth- 3 Prop- 4 But- 5 Pent- 6 Hex- 7 Hept- 8 Oct- 9 Non- 10 Dec- Naming Straight-Chained Alkanes Find the longest continuous chain of C atoms – this is the parent chain Use the appropriate prefix based on the number of C atoms in the main chain Add the suffix “–ane”

Naming Branched Alkanes Many hydrocarbons are not simple straight- chained molecules and involve a great deal of branching.

Naming Branched Alkanes Identify the main chain and name it accordingly Count the carbons in the parent chain, giving the lowest number to the end closest to a branch Identify each branch and name it using the appropriate prefix and the suffix “–yl” Indicate the number of each size of branch using an additional prefix (di, tri, tetra, etc.) Place the names of the branches in front of the parent chain in alphabetical order Indicate the position of the side chain by indicating the carbon # it is attached to (in front of the branch name)

Example: Branched Chain Alkane 1 2 3 4 5 6 Parent chain: hexane Branches: 3,4-dimethyl Name of compound: 3,4-dimethylhexane Please note that all numbers and letters are separated by a hyphen

Example: 4-ethyl-2,2-dimethylhexane