Ch' 22: Organic Chemistry

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Ch. 22 Organic Chemistry

• 22.1 Alkanes

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Alkanes

• saturated hydrocarbons
• only single bonds
• each C has 4 atoms bonded to it
• all C have tetrahedral arrangement
• sp3 hybridization
• straight-chained, normal, unbranched hydrocarbons
• with no substituent groups
• are long chain alkanes

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Alkanes

• really a zigzag shape because of 109.5 in C-C-C
  bond
• structural isomers-
• different molecules with same atoms (formula)
• different bonding
• have different properties

C4H10
C4H10
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Naming

• Find the longest chain of carbons
• count the number and find the prefix
• name is prefix and ane ending for alkanes
• If there are substituent groups, number the
  carbons in the chain from one end to the other
• make the s for groups as small as can
• Name the groups by taking the prefix for the
  number of carbons in the group and add -yl

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Naming

• the positions of each group are given by the s
  of the carbon they are attached to
• put hyphen between and group and a comma
  between s
• For more than 1 group, list then in alphabetical
  order
• add prefix (di, tri, etc) if there are more than
  one of the same type

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Practice Naming

• longest chain is 3
• name propane
• 1 C group methyl group
• off of 2 carbon
• 2-methylpropane
• longest chain is 3
• 2- methyl groups
• 2,2-dimethylpropane

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Practice Naming
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Reactions with Alkanes

• fairly unreactive
• combustion
• always added to O2
• always makes CO2 and H2O
• substitution
• when a halogen is added to it, one halogen may
  replace one hydrogen
• CH4 Cl2 ? CH3Cl HCl
• dehydrogenation
• 2H atom are removed to form unsaturated
• CH3CH3 ? CH2CH2 H2

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Cyclic Alkanes

• cyclopropane
• planar unstable
• cyclobutane
• planar and unstable
• cyclopentane
• planar and stable
• cyclohexane
• puckered and stable

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Unsaturated Alkenes and Alkynes

• alkenes contain at least one double bond
• alkynes contain at least one triple bond
• change the ending of name to ene or yne
• add a telling the starting position of the
  special bond

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Unsaturated Alkenes and Alkynes

• can also have unsaturated rings
• cyclohexene
• double bonds prevent rotation
• cis-trans isomerism
• cis- identical groups on same side of bond
• trans identical groups on opp side of bond

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Reactions Alkenes and Alkynes

• Addition Reactions
• Hydrogenation
• add hydrogen pair to remove special bond
• CH2CHCH3 H2 ? CH3-CH2-CH3
• Halogenation
• add halogen pair to remove special bond
• CH2CHCH3 Br2 ? CH2Br-CHBr-CH3

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Aromatic Hydrocarbons

• cyclic unsaturated hydrocarbons
• benzene
• phenyl group when attached to a chain

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functional groups