Chemical Nature of Carbon Valence electrons? Ionic bonding? Number of bonds?

2 Uses of Hydrocarbons Number of C atoms StateMajor Uses 1-4gas heating and cooking fuel 5-7 liquids, (low boiling) solvents, gasoline 6-18liquidsgasoline 12-24liquids jet fuel; camp stove fuel liquids, (high boiling) diesel fuel, lubricants, heating oil 50+solids petroleum jelly, paraffin wax 1-4gas heating and cooking fuel 5-7 liquids, (low boiling) solvents, gasoline 6-18liquidsgasoline 12-24liquids jet fuel; camp stove fuel liquids, (high boiling) diesel fuel, lubricants, heating oil 50+solids petroleum jelly, paraffin wax

Tro, Chemistry: A Molecular Approach 3 Saturated Hydrocarbons a saturated hydrocarbon has all C-C single bonds – it is saturated with hydrogens saturated aliphatic hydrocarbons are called alkanes chain alkanes have the general formula C n H 2n+2

4 Formulas

Tro, Chemistry: A Molecular Approach Formulas

6 Isomerism Isomers = different molecules with the same molecular formula Structural Isomers = different pattern of atom attachment

Tro, Chemistry: A Molecular Approach 7 Rotation about a bond is not isomerism

Tro, Chemistry: A Molecular Approach 8 Possible Structural Isomers

Naming Alkanes Compounds are given systematic names by a process that uses Follows specific rules – Find parent hydrocarbon chain – Carbons in that main chain are numbered in sequence – Substituents are identified numbered – Write compound name is single word – Name a complex substituents as though it were a compound itself

11 Naming Alkanes 1)Find the longest continuous carbon chain 2)Number the chain from end closest to a branch – if first branches equal distance use next in 3)Name branches as alkyl groups – locate each branch by preceding its name with the carbon number on the chain 4)List branches alphabetically – do not count n-, sec-, t-, count iso 5)Use prefix if more than one of same group present – di, tri, tetra, penta, hexa – do not count in alphabetizing

Tro, Chemistry: A Molecular Approach 12 Alkyl Groups

Tro, Chemistry: A Molecular Approach 13 More Alkyl Groups BUTYL

Tro, Chemistry: A Molecular Approach 14 Drawing Structural Formulas draw and number the base chain carbon skeleton add the carbon skeletons of each substituent on the appropriate main chain C add in required H’s 4-ethyl-2-methylhexane

Tro, Chemistry: A Molecular Approach 15 Reactions of Hydrocarbons all hydrocarbons undergo combustion combustion is always exothermic – about 90% of U.S. energy generated by combustion 2 CH 3 CH 2 CH 2 CH 3 (g) + 13 O 2 (g) → 8 CO 2 (g) + 10 H 2 O(g) CH 3 CH=CHCH 3 (g) + 6 O 2 (g) → 4 CO 2 (g) + 4 H 2 O(g) 2 CH 3 C  CCH 3 (g) + 11 O 2 (g) → 8 CO 2 (g) + 6 H 2 O(g)