Transcript Organic Molecules

Organic Chemistry
AP Chemistry Ch. 22
Assignment:
Read Ch.22 (especially 22.1 – 22.5)
• Organic HW packet - due the day you return!
• Organic unit quiz – second class of new semester.
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Organic:
pertaining to carbon compounds
Organic molecules contain carbon,
except for the following:
• no
carbon oxides (CO, CO2)
• no carbonate ions (CO32−)
• no cyanide ions
(CN−)
• no carbon disulfide (CS2)
Which of the following are organic?
CaCO3
CH4
CH3CH3
CO2
NH3
C6H12O6
CO
CH3OH
Organic Compounds
•Many
are insoluble in water
•low melting points & boiling points
•Decompose easily
•combustible
Hydrocarbons
•molecules
made up of hydrogen and carbon.
•Fossil fuels
Naming: the root is based on the number
of carbon atoms in the chain
methethpropbutpent-
1
2
3
4
5
hexheptoctnondec-
6
7
8
9
10
The ending (suffix) depends on the types of
bonds between the carbon atoms.
Alkanes:
Hydrocarbons with only single bonds
• Saturated since they contain the maximum
number of H or other atoms possible.
• tetrahedral shape around each carbon
• zig-zag (not linear) shapes
• sp3 hybridization
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Naming the Alkanes:
Start with the root representing the number of
carbons in the chain.
• Add “-ane” to the end to show C-C bonds.
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Alkane General Formula
CnH2n+2
• The number of H atoms = two times the
number of C atoms plus two more.
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Name these alkanes:
CH4
CH3-CH2-CH3
CH3-CH2-CH2-CH3
methane
propane
butane
There are different methods used to write organic
compound formulas. The following all represent
butane:
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C4H10
is the molecular formula
is the condensed structural formula
is the structural formula
is the line formula - each endpoint of the line
formula represents a carbon. Hydrogens are not
drawn, but assumed to be present since each carbon
forms four bonds.
← Click this link
if you need more
information on
types of formulas.
Structural Isomers
Molecules with the same numbers of atoms of
each element, but different structural
arrangements.
•These different structures result in different
properties, such as boiling/melting points, IMF’s…
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Branched Hydrocarbons
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a carbon atom bonded to three or four
carbon atoms
Naming Branched Hydrocarbons
1. Name the longest carbon chain (called the parent chain)
2. Name the branches using the suffix “-yl”.
3. Number the carbons on the parent chain, starting with the
end closest to the branch(es).
4. Put it together in this order:
# of carbon with branch
-branch name
Parent chain name
CH3 ← “methyl”
1
2
3
CH3-CH -CH3 ←“propane”
2-methylpropane
Naming Branched Hydrocarbons
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For multiple branches, list them in
alphabetical order
If you have more than one of the same
type of branch, include a prefix to show
how many of these branches you have.
is “3,3-dimethylpentane”.
Ignore the prefixes for putting branches in
alphabetical order.
Name this compound:
CH3
CH3-CH2-CH -CH3
2-methylbutane
Name this compound:
CH3
CH3-CH2-CH -CH3
CH3
2,3-dimethylbutane
Name this compound:
CH2-CH3
CH3-CH2-CH2-CH2-CH-CH2-CH3
3-ethyl heptane
Reactions with Alkanes
Combustion:
2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g)
Substitution:
• something replaces a hydrogen on the hydrocarbon
• CH4 + Cl2  CH3Cl + HCl
Dehydrogenation:
• Hydrogen is removed from the hydrocarbon
• CH3CH3  CH2=CH2 + H2
Cyclohydrocarbons (Cyclic)
Hydrocarbons that contain a ring.
• Names: add “cyclo-” just before the ring name.
• Carbon ring is numbered to give the branches the smallest
numbers
• Larger branches are given the lower numbers on the ring
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cyclopentane
cyclohexane
Alkene
a hydrocarbon containing at least one
double bond (making it unsaturated).
• Name ends with “ene”
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Alkyne
a hydrocarbon containing at least one
triple bond (making it unsaturated).
• Name ends with “yne”
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Stereo Isomers
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Same atom-atom bonds, but different locked
orientations
Pi (double/triple) bonds prevent rotation.
2 orientations:
cis (same side):
trans (opposite side):
Name these compounds:
I:
cis-1,2-dichloroethene
II: trans-1,2-dichloroethene
Addition Reactions: Alkenes and Alkynes
Hydrogenation:
Hydrogen is added reducing the multiple bond
• CH2=CHCH3 + H2  CH3CH2CH3
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Halogenation:
A halogen is added removing the multiple bond
• CH2=CHCH3 + Br2  CH2Br-CHBr-CH3
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Polymerization:
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Small molecules are joined into large molecules
Name these hydrocarbons:
CH3-CH2-CH2-CH3
butane
CH3-CH=CH-CH3
2-butene
1-butyne
CH3-CH2-C=CH
CH3-CH2-CH≡CH-CH2-CH3
3-hexene
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH3
octane
Name this compound:
CH3-CH2-CH=CH-CH3
2-pentene
Name this compound:
3,5,5-trimethyl-3-heptene
Draw a condensed structural
formula for:
3,3,4,4-tetramethyl-1-hexyne
•a
Benzene (C6H6)
ring of 6 carbon atoms with alternating single
and double bonds
•Delocalized pi electrons
Aromatic Hydrocarbons
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Formed from Benzene rings
phenyl group: when attached to a chain
Functional Groups
any element or group that replaces hydrogen on a
hydrocarbon.
• “R” represents the carbon chain
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Halocarbons: R-X
Alcohols:
R-OH
Aldehydes:
R-CO-H
Ketones:
R-CO-R’
Carboxylic Acids: R-CO2H
Esters:
R-CO2-R’
Ethers:
R-O-R’
Amines:
R-NH2
Halocarbons: R-X
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the functional group on a
hydrocarbon is a halogen (“X”).
Halocarbon Names
# of carbon where halogen is bonded
• Halogen name ending with “o”
(Cl is “chloro”)
• Parent chain name
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CH2F-CH2-CH2-CH3 is 1-fluorobutane
Name these compounds:
CH3-CCl2-CH2-CH3 2,2-dichlorobutane
CHBrCl-CH2Br 1-chloro-1,2-dibromoethane
CH2Cl-CHCl-CH2-CH3 1,2-dichlorobutane
CH2F-CHBr-(CH2)4-CH3
1-fluoro-2-bromoheptane
Note: the (CH2)4 represents four CH2 groups in a chain
CHClF-CH2-CHF-CH2-CH3
1-chloro-1,3-difluoropentane
Alcohols: R-OH
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have an -OH functional group called a
hydroxyl group.
Parent chain suffix replaced by “-ol”
Types of Alcohols:
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Primary: the carbon bonded to the
-OH group is bonded to only one
other carbon.
Secondary: -OH group’s carbon is
bonded to two other carbon atoms
(-C-CHOH-C-)
Tertiary: the hydroxyl’s carbon is
bonded to three other carbon atoms
Name these compounds and identify
the type of alcohol:
CH2OH-CH3
1-ethanol, primary
CH3-CH2-CHOH-CH3 2-butanol, secondary
Aldehydes
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have a carbonyl group
the carbon chain
Names end with “-al”
propanal
at the end of
Ketones
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Have a carbonyl group in the carbon
chain (not on an end carbon)
Names end with “-one”
acetone
Carboxylic Acids:
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-COOH functional group called a carboxyl
group.
Names end with “-oic acid”
Esters
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Have a carboxyl group in the carbon chain
(not on an end carbon)
Butyl ethanoate
Ethers
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R-O-R’
Oxygen is between two carbon atoms
Amines: R – NH2
• a nitrogen group bonded to the
carbon chain
Polymers
•large
organic compounds made up of
repeating units
“poly” = many
• “mer” = parts
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monomers- the small molecules that make
up polymers
very important in making plastics, rubber
materials, synthetic fibers, etc.
Homework Packet notes:
The table on the back side of p.1 is found in your book on
p.1009. You are copying this information into your own
table.