Transcript Organic Chemistry

Organic Chemistry
…oh what fun…
Organic Chemistry
What does it mean to be organic?
 To be an organic compound means that
you contain carbon
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… that’s it… if you contain carbon, you are
organic
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There are a few exceptions, but you don’t have to
worry about those
Carbon atoms comprise about 20% (by mass)
of all animals
Fossil Fuels
Common products like plastic, adhesives,
soaps, etc
Organic Compounds
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Why so many carbon compounds?
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Carbon is tetravalent
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Four bonding electrons – this means carbon can form
long chains and rings with other carbon atoms
Carbon atoms form single, double, and triple
covalent bonds
The same atom can join together to produce
isomers (molecules with the same formula,
but different structures)
Homologous Series
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Homologous Series:
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General formula can be written to represent all
member of a series
Each successive member of the series differs
by a common structural unit
The chemistry of any one member is similar to
that of the other members
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Similar preparation and similar chemical properties
Formulae
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Molecular Formula
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Structural Formula
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Tells the number of atoms in a molecule, but
not the arrange of the molecules (H2O)
Shows the arrangement of atoms in a molecule
Can show all atoms and bonds
Condensed Structural Formula
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Shows all bonds expect bonds to hydrogen, or
only shows the bonds to the substituents
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CH3-CH2-CH2-OH
Simplest Organic Compounds
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Simplest organic compounds are
hydrocarbons
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Meaning that they only contain carbon and
hydrogen
Hydrocarbons
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Alkanes – only single bonds b/w carbons
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Alkenes – at least 1 double bond b/w
carbons
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General Formula: CnH2n+2
General Formula: CnH2n
Alkynes – at least 1 triple bond b/w
carbons
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General Formula: CnH2n-2
Functional Groups
An atom or group of atoms that always
react a certain way
 Adding a functional group to a
hydrocarbon will always change the
physical and chemical properties of that
hydrocarbon
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And a functional group will always change
these properties the same way
Functional Groups
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Halide (Haloalkane)
Alcohol
Ether
Aldehyde
Ketone
Organic acid
Ester
Amine
Amide
Carbonyl Group: carbon with a
double-bonded oxygen
Halide (Haloalkane)
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Compound containing a halogen (or group
17 of the periodic table) bonded to the
compound
General Formula:
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R- X
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R= compound, X = halogen
Example:
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CH3CHClCH3
2-chloropropane
Amine
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Contain nitrogen atoms bonded to carbon
atoms
General Formula:
R’’
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R- N- R’
Example:
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CH3CH2CH2NH2
1-propanamine
Alcohol
Compound where a hydroxyl group (-OH)
replaces one of the hydrogens on a carbon
 General Formula:
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R- OH
Example:
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CH3CH2CH2OH
1-propanol
Organic (Carboxylic) Acid
Compound with a carboxyl group (a
carbonyl group bonded with an alcohol)
 General Formula:
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Example:
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propanoic acid
Physical Properties of Organic
Compounds
Colour: colourless
 State @ Room Temp:
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Hydrocarbons: gases then liquids, then solids
as molar mass increases
Haloalkanes, alcohols, carboxylic acids and
amines: liquids then solids as molar mass
increases
Physical Properties of Organic
Compounds
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Solubility in Water:
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Hydrocarbons and Haloalkanes insoluble (nonpolar)
Alcohols, carboxylic acids and amines:
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Lower molar mass members are soluble in water
(polar)
Higher molar masses insoluble
 The more carbons, the less polar it becomes
Naming Hydrocarbons
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There is very simple nomenclature for
hydrocarbons
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First of all, we’ll start with naming straight
chains
1.
2.
Each chain that contains only single bonds ends with
–ane
Count the carbons and add the correct the prefix for
that number of carbons.
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What are the prefixes?
Naming Hydrocarbons
Number of Carbons
Prefix
1
2
3
4
MethEthPropBut-
5
6
7
PentHexHept-
8
9
10
OctNonDec-
Practice Naming:
Butane
Practice Naming:
Heptane
Practice Naming:
Heptane
Different Diagrams
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There are different ways to represent
carbon chains.
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1) there is the standard way where you draw
in every hydrogen atom
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2) You can simply draw in dashes and not label
the ‘H’ s because we know what they are
Different Diagrams
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3) The stick-figure drawing
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Here we know that each carbon has 4 bonds and we
can leave out the bonds for hydrogen completely
Here we count each point on this line as a carbon
So what is it?
 PENTANE
Naming Branched Alkanes:
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What do you do if it’s not a straight chain?
Naming Branched Hydrocarbons
How to Name Branched Chains
1.
Find and name the longest “straight”
chain
(This doesn't mean that the carbons all have to
be in one straight line... you just have to be
able to connect them with one pen-stroke)
What is the longest chain in this molecule?
Hexane
How to Name Branched Chains
2.
Locate your branches. Name these like
you name regular hydrocarbons, except
these will end with -yl (instead of -ane)
What is the name of the branch on this
molecule?
Methyl … so now we have methyl-hexane
How to Name Branched Chains
3.
Tell me where the branch is located.
(b)
Start counting so you have the lowest
number combination possible...
So let's name this one again...
(c)
2-methyl-hexane
(a)
How to Name Branched Chains
4.
If there are multiple chains, the naming
order is: where the chains are, how
many, what they are
How to Name Branched Chains
5.
If the branches have different names
(methyl vs. ethyl for example)...
arrange them alphabetically in the name