Introduction to Alkanes

The structures of methane, ammonia, and waterareall based on a tetrahedral arrangement of electron pairs around the central atom, with the central atoms being sp hybridized. Methane has four bonding pairs of electrons, ammonia three bonding pairs and one lone pair, and water two bonding pairs and two lone pairs. Exact shapes may be predicted by VSEPR. 

The structures of many molecules can be derived as substituted versions of methane, ammonia, and water. 

There are various two-dimensional representations of three-dimensional molecules— wedge, sawhorse, and Newman representations. 

Complex organic molecules are represented as stick drawings, with hydrogen atoms omitted, and carbon atoms represented by vertices. 

Organic chemists tend to have a limited interest in alkanes, despite their being some of the most abundant organic molecules on the planet. Abundant yes, reactive no—their most important reaction is combustion. Much of the energy used in the developed world derives from the burning of hydrocarbons, in one form or another. Alkanes are the simplest of hydrocarbons, with a general formula d no multiple bonds. They are nonpolar 

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Introduction to Alkanes and Cycloalkanes 143 THE CHEMISTRY OF... Petroleum Refining 143... 

Introduction to Alkanes Methane, Ethane, and Propane 57 sp Hybridization and Bonding in Methane 58... 

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