Organic Chemistry Chapter 1: Alkanes and Chemical Bonds

Study Notes

Ionic bonds result from the transfer of electrons
Covalent bonds result from the sharing of electrons
Covalent bonds are typical of carbon compounds and are of chief importance in organic chemistry

Hybrid orbitals are formed by mixing (hybridizing) carbon's atomic orbitals
When carbon bonds to 4 other atoms, the 2s orbital and all three 2p orbitals in the valence shell combine to produce four sp3 hybrid orbitals
Hybrid orbitals are used to describe the bonds between carbon atoms

Carbon has sp hybridization when bound to two other atoms with the help of two double bonds or one single and one triple bond
sp hybridization results in a linear arrangement of atoms with a bond angle of 180°

Carbon is sp2 hybridized when bonding takes place between 1 s-orbital with two p orbitals
sp2 hybridization results in a triangular arrangement of atoms with 120° angles between bonds

Carbon has sp3 hybridization when bonded to four other atoms
sp3 hybridization results in a tetrahedral arrangement of atoms with a bond angle of 109.5°
Example: Hybridization of CH4 (Methane)

Alkanes are nonpolar, making them insoluble in water but soluble in nonpolar solvents
Alkanes have densities from 0.62 g/mL to about 0.79 g/mL, which is less than the density of water (1.0 g/mL)
Alkanes with 1-4 carbon atoms are gases at room temperature and are widely used as heating fuels
Alkanes with 5-9 carbon atoms are liquids at room temperature and are used in fuels such as gasoline
Alkanes with 9-17 carbon atoms have higher boiling points and are found in kerosene, diesel, and jet fuels
Alkanes with 18 and more carbon atoms are waxy solids at room temperature and are used in waxy coatings
Alkanes with 25 and more carbon atoms are semi-solid mixtures of hydrocarbons used in ointments, cosmetics, and as a lubricant (e.g. Vaseline)

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