Download Chapter 14 – Organic Chemistry

Chapter 10 – Organic Chemistry
Organic Chemistry:
- study of carbon and carbon compounds
Organic Compounds:
- compounds which contain both carbon and hydrogen
- carbon atoms bond together to form chains, branches, rings, or
networks
Characteristics of Organic Compounds:
- covalent bonding
- carbon forms 4 bonds to make a tetrahedron – results in LARGE
molecules
Ex: CH4
- nonpolar (no end is positive, and no end is negative)
- soluble in nonpolar solvents
- generally nonelectrolytes except for organic acids (Ex: acetic
acid)
- low melting points due to weak intermolecular forces (van der
Waal’s)
- generally slow reactions due to complex structures and high
activation energies
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Structural Formulas
- single bonds ( – ): one pair of shared electrons
- double bonds (=): two pairs of shared electrons
- triple bonds (
): three pairs of shared electrons
Ex:
Saturated vs. Unsaturated
saturated:
- all carbon to carbon bonds are single
- full of hydrogens
unsaturated:
- contains one or more double or triple bonds
- “missing” hydrogens
Homologous Series of Hydrocarbons
Hydrocarbons: contain only hydrogen and carbon
PREFIXES
meth
Eth
prop
but
pent
# OF CARBON ATOMS
1
2
3
4
5
2
SUFFIXES
-ane
-ene
-yne
TYPE OF BOND
all single bonds
one double bond (unsaturated)
one triple bond (unsaturated)
A. Alkanes:
-
single bonds only
saturated (C – C)
CnH2n+2 (see Ref. Table Q)
Each alkane differs from the next by one CH2
Ex: Methane:
- the first member of the alkane series
- ends in “-ane” because it is part of the alkane series
- begins with “meth” because it has one carbon atom (See
Reference Table P)
- Use Reference Table Q to find the molecular formula of
methane:
- Draw methane:
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Ethane:
How many carbon atoms does ethane have?
Write the molecular formula for ethane:
Draw ethane:
Propane:
How many carbons does propane have?
What is the molecular formula for propane?
Draw propane:
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Condensed Structural Formula:
- use for larger molecules
- draw lines between carbon atoms but not between carbon and
hydrogen atoms
What is the condensed structural formula for propane?
Butane:
How many carbon atoms does butane have?
What is the molecular formula for butane?
Draw butane:
Here is another structural formula for C4H10. How do you name this
compound?
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1. Count t he number of carbon atoms in the longest unbroken chain
of carbon atoms.
- this compound has a 3-carbon chain as its longest chain
- “prop-“
2. Determine if the bonds are all single or if double and triple bonds
exist.
- this compound only has single bonds
- “-ane”
3. Determine what the branched group is and to which carbon in the
longest chain it is attached.
- CH3 is attached to the second carbon in the chain and it is a
methyl group (1 hydrogen less than methane)
The compound is called 2-methylpropane
Isomers:
- compounds that have the same molecular formula but different
structural formulas
Ex: butane and 2-methylpropane
Ex: pentane and 2,2-dimethylpropane
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Alkyl Groups:
- have one less hydrogen than the corresponding alkane
Ex:
CH3 is a methyl group.
C2H5 is an ethyl group
C3H7 is a propyl group.
Alkenes:
- unsaturated (C = C)
- has one double bond (Note: if a compound has more than one double
bond, it is not an alkene; it is called a diene)
- CnH2n
- To name alkenes, use the same beginnings as with alkanes, but change
the ending to “-ene”
- Note: there is no methene!!
Ethene:
How many carbons does ethene have?
What is the molecular formula of ethene?
Draw ethene:
Propene:
How many carbons does propene have?
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What is the molecular formula of propene?
Draw propene:
Alkynes:
- unsaturated (C C)
- has one triple bond
- CnH2n-2
- To name alkynes, use the same beginnings, but end in “-yne”
Ethyne:
How many carbon atoms does ethyne have?
What is the molecular formula of ethyne?
What is the structural formula of ethyne?
Propyne:
How many carbon atoms does propyne have?
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What is the molecular formula of propyne?
What is the structural formula of propyne?
Benzene Family:
- ring-shaped hydrocarbons
- aromatic
- CnH2n-6
C6H6
benzene
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C7H8
toluene
NOTE: in all homologous series, each successive member differs by
CH2
Other organic compounds:
Functional Group:
- specific group of atoms that gives a molecule its characteristic
properties.
- SEE REFERENCE TABLE R!!!
Ex:
alcohols: (-OH)
acids: (-COOH or
aldehydes: (- CHO or
)
)
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A. Alcohols
- organic compounds in which one or more hydrogens of a
hydrocarbon are replaced by an OH group
- in alcohols, the OH group is called a hydroxyl group
Naming Alcohols:
1. drop the “-e” from the corresponding alkane
2. add an “-ol”
Ex: drop the “-e” from methan”e” and add “-ol”
METHANOL
Name the following alcohols:
These are all examples of monohydroxy alcohols, because they have
only one OH group
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Another Example:
This alcohol is called 1,2 ethanediol
- Ethane because it has 2 carbon atoms with single bonds
- diol because there are 2 OH groups
- 1,2 because the OH group is attached to the first and second
carbon atoms
- Common name of this alcohol is ethylene glycol
- This is a dihydroxy alcohol because it has 2 OH groups
And Yet ANOTHER Example!
This alcohol is called 1,2,3 propanetriol
- Propane because it has three carbons all with single bonds
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- triol because it has three OH groups
- 1,2,3 because the OH groups are attached to the first, second,
and third carbon atoms
- Common name of this alcohol is glycerol
- This is a trihydroxy alcohol because it has 3 OH groups
For Your Information!
Whenever you see an “R” it is symbolizing a hydrocarbon chain!!!
So! Remember!!!
R = a hydrocarbon chain
Some more information on monohydroxy alcohols (ROH)
- Have only one OH group
a. primary alcohols
- the carbon that is attached to the OH group is attached only to
one carbon or to no carbons
C3H7OH
or
CH3CH2CH2OH
1 – propanol
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b. Secondary Alcohols:
- the C attached to the OH is attached to two other carbons
C4H9OH
2-butanol
c. Tertiary Alcohols:
- the C attached to the OH is attached to three other carbons
C5H11OH
2-methyl 2-butanol
Drawing Alcohols:
Draw the structural formula of butanol:
Draw the structural formula of pentanol:
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Draw the structural formula of hexanol:
Draw the structural formula of heptanol:
B. Aldehydes:
- have the functional group:
- single bond between C and H
- double bond between C and O
Example of an Aldehyde:
Naming Aldehydes:
1. Drop the final “e” from the corresponding alkane
2. Add “-al”
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Name the following aldehydes:
Drawing Aldehydes:
Draw the structural formula for butanal:
Draw the structural formula for pentanal:
Draw the structural formula for hexanal:
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C. Ketones:
- have the functional group:
- “C = O” bond is in the middle and carbon atoms are on both
sides
Example of a Ketone:
Naming Ketones:
1. drop the final “e” from the corresponding alkane
2. add “-one”
Name the following ketones:
Drawing Ketones:
Draw the structural formula for 2 – pentanone:
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Draw the structural formula for 2 – hexanone:
Draw the structural formula for 2- heptanone:
D. Organic Acids:
- have the functional group: COOH
- Shown in Table R by:
- “R” can be CH3 (methyl) or C2H5 (ethyl)
Example of an Organic Acid:
Naming Organic Acids:
1. Drop the final “e” from the corresponding alkane
2. Add “-oic acid”
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Name the following Organic Acids:
methanoic acid
(formic acid)
HCOOH
ethanoic acid
(acetic acid)
CH3COOH
propanoic acid
CH3CH2COOH
or
C2H5COOH
Drawing Organic Acids:
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Draw the structural formula of butanoic acid:
Draw the structural formula of pentanoic acid:
Draw the structural formula of hexanoic acid:
E. Ethers:
- Functional group of ether is – O –
- Ethers can be shown by R – O – R’
- There is always an O in between two carbon atoms
Examples of Ethers:
dimethyl ether
CH3OCH3
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diethyl ether
(ether)
CH3CH2OCH2CH3
methylethyl ether
CH3OCH2CH3
Drawing Ethers:
Draw ethyl propyl ether:
Draw dipropyl ether:
F. Halides (a.k.a. halocarbons):
- one or more halogens attached to a carbon atom or a chain of
carbon atoms
- Just in case you forgot…the halides are F, Cl, Br, and I
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Example of a Halide:
2-bromobutane
Drawing Halides:
Draw the structural formula for 3-fluoroheptane:
Draw the structural formula for 2-iodohexane:
Draw the structural formula for 3-bromohexane:
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G. Amines:
- has functional group – N –
- functional group is attached to carbon or hydrogen atoms
Example of an Amine:
Naming Amines:
1. Drop the final “e” in the corresponding alkane
2. Add “-amine”
Name the following amines:
Drawing Amines:
Draw the structural formula of butanamine:
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Draw the structural formula of pentanamine:
Draw the structural formula of hexanamine:
H. Amino Acids (NOT IN TABLE R!):
- have both an amine and an organic acid
- General formula for amino acids:
- When you see NH2 and COOH, you know it is an amino acid!
I. Amides:
- Have the functional group
at the end
of a carbon chain
- Carbon is attached to oxygen by a double bond
- Carbon is attached to the –NH (amine group) by a single bond
Naming Amides:
1. Drop the final “e” from the corresponding alkane
2. Add “-amide”
Name the following amide:
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Drawing Amides:
Draw the structural formula for butanamide:
Draw the structural formula for pentanamide:
Draw the structural formula for hexanamide:
J. Esters:
- Have the functional group
between two carbon
chains
- Carbon is attached to one oxygen by a double bond
- Carbon is attached to another oxygen by a single bond
Example of an Ester:
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Naming Esters:
1. Look at the carbon chain after the
2. Write its prefix (ex: meth-, eth-, etc.) and add –yl to the end of the
prefix
3. Give the name of the carbon chain that includes the C = O
4. Leave off the last letter and add “-oate”
Name the Following Esters:
Drawing Esters:
Draw the structural formula for methyl butanoate:
Draw the structural formula for ethyl pentanoate:
Draw the structural formula for methyl hexanoate:
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Effect of Functional Groups on Physical Properties:
1. Boiling Points:
A. Alcohols and Acids
- hydrogen bonds in alcohols and acids cause the boiling point to
be higher than in the alkane with the same number of carbons
B. Amines
- also have a hydrogen bond, but it is weaker than that seen in
alcohols and acids
- Boiling point is higher than in the corresponding alkane, but
lower than in alcohols and acids
-
C. Ethers, Aldehydes, and Ketones
oxygen is not bonded to hydrogen (so no hydrogen bonds)
however, these are polar molecules which have intermolecular
forces
IMF is weaker than hydrogen bond
Boiling point is higher than in corresponding alkane, but lower
than in alcohols and acids
D. Hydrocarbons
- no hydrogen bonds
- nonpolar molecules
- lower boiling point than in alcohols, acids, amines, esthers,
aldehydes or ketones
2. Melting Points:
- follow the same pattern of boiling points for the same reasons
3. Solubility:
- Remember! Polar substances dissolve in polar solvents (water)
- LIKE DISSOLVES LIKE!!!
A. Small alcohols, acids, ethers, aldehydes, and ketones are
polar and dissolve in water
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NOTE: When there are many carbon atoms, the nonpolar
carbon atoms become more important and the molecule does
not dissolve as well in water
B. Hydrocarbons are nonpolar and do not dissolve in water
I.
Organic Reactions
A. Substitution:
- Replacement of one kind of atom or group by another kind of
atom or group
- something substitutes for hydrogen in a saturated hydrocarbon
- two products
Chloroethane
B. Addition:
- something is added to an unsaturated hydrocarbon at a double or
triple bond
- one product
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1,2-dichloroethane
“halogenation”
“hydrogenation”
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C. Fermentation:
- sugars are converted to alcohol and CO2 by yeast enzymes
zymase
C6H12O6
2 C2H5OH
+
2 CO2
D. Esterification:
- Acid and alcohol produce ester and water
- acid + alcohol
RCOOH
+
ester + H2O
R′OH
RCOOR′ + H2O
E. Saponification
- ester breaking up into an acid and alcohol (reverse of
esterification)
- hydrolysis of fats by a strong base
- yields soap and glycerol
3 RCOOH
fat
+
3 NaOH
base
3RCOONa
soap
+ C3H5(OH)3
glycerol
F. Oxidation
- reacting with oxygen
- saturated hydrocarbons burn completely to yield CO2 and H2O
CH4
+ 2O2
CO2
+ 2H2O
- burn incompletely (limited O2) to yield C and CO
G. Condensation Polymerization:
- saturated monomers (small molecules) are connected with the
removal of water (dehydration synthesis)
amino acid + amino acid + amino acid
Protein + H2O
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- Ex: nylon, polyester, silicone
- Naturally occurring polymers: starch, protein, cellulose
H. Addition Polymerization:
- unsaturated monomers add together at the double bond
nC2H4
ethene
(C2H4)n
polyethylene
ethene + ethene + ethene
polyethylene
Finding Missing Reactants and Products in Organic Reactions:
- in an equation, the number of atoms on the left side of the arrow
must equal the number of atoms on the right side of the arrow
- you can only change the coefficients in from of elements or
compounds
Find the missing product in this balanced equation:
C2H6 + Cl2
C2H5Cl +
Count the number of atoms of each element on each side of the
arrow:
Left Side
C: 2 atoms
H: 6 atoms
Cl: 2 atoms
Right Side
C: 2 atoms
H: 5 atoms
Cl: 1 atom
Missing on Right Side
NONE
H: 1 atom
Cl: 1 atom
HCl must be the missing atom!
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Find the missing reactant in this balanced equation:
C2H4 +
Left Side
C: 2 atoms
H: 4 atoms
Br: none
C2H4Br2
Right Side
C: 2 atoms
H: 4 atoms
Br: 2 atoms
Atoms Missing From Left Side
NONE
NONE
Br: 2 atoms
The missing reactant is Br2!
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