Transcript Organic Chemistry

Chapter 20
Organic
Chemistry
Objective: Students will understand
how to name the alkanes.
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What is ORGANIC Chemistry?

The study of carbon-containing compounds
(typically chains of carbon atoms) and their
properties.
 Carbon atoms can link to other carbon
atoms indefinitely.
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HYDROCARBONS

Compounds containing carbon and
hydrogen only. There are several classes.
 The first is ALKANES.
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ALKANES

Alkanes are the simplest of the hydrocarbons.
They only contain carbon-hydrogen bonds and
carbon-carbon single bonds. The first ten are:
 Their formulas are always
 CxH2x+2 C6H14 is an example
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TEN ALKANES
The names
of the
Alkanes
always end
in -ane
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Figure 20.2: The Lewis structure of ethane.
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Name the Compound
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What is a branched-chained alkane?
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Naming Branched
Chained Alkanes

Page 641 of your text
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Naming Branched
Chained Alkanes

Page 641 and 642 of your text
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Naming Branched
Chained Alkanes

Page 643 of your text
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Naming Branched
Chained Alkanes

Page 643 of your text
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Name the Compound
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Name The Compound
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Calculating the molar-mass
Branched Chained Alkanes

Calculating the molar mass of alkanes is easy.
 1. Determine the total number of carbons and
times that number by 12.
 2. Then determine the number of hydrogens. (
2x the carbons + 2 more)
 3. Add the two together.
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Calculating the molar-mass
Branched Chained Alkanes

Example:
Find the molar-mass of 2,3-dimethylpentane.
 There are 5 carbons in pentane and 1 carbon in
each methyl so a total of 7.
 That means there are a total of 16 hydrogen
atoms.
 12 x 7 + 16 = 84 + 16 = 100
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Isotopes of Butane
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Stop here for the
st
1
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Assignment
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ISOMERS
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C2H6O
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What is a BLEVE?
An acronym for “boiling liquid escaping
vapor explosion
 VIDEO #1 After watching explain how a
bleve happens
 Video #2
 Video #3 Notice how the fire keeps its shape

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A closer look at this fire
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Propane
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Properties of ALKANES
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Alkenes

Alkenes are hydrocarbons with double bonds.
They are unsaturated and often referred to as
“olefins”
 The name of alkenes end in –ene.
 Ethene, Propene
Butene
Pentene
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Cis and Trans

Double bonds on the carbons prevents the
carbon atoms from rotating around each
other.
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Naming Alkenes

When naming alkenes give the lowest
number to the double bond.
 Then name the side chains
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Name the compound

Trans-3-heptene
 4-methyl-cis-2 pentene
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Butadiene

Butadiene is butane with two double bonds
 C=C-C=C 2,3-butadiene
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Cyclo-hydrocarbons

Hydrocarbons that are in a ring are called
cyclo-hydrocarbons
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Alkynes

Alkynes are hydrocarbons that have a triple
bond. They are very reactive.
 Video controlled explosion of ethyne.
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Naming Aromatic Compounds
BENZENE

Objective: Students will understand the
historical significance of Benzene, its
structure and how to name compounds
containing benzene.
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Figure 20.8: Two Lewis structures for the benzene ring.
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1.3.5-Cyclohexatriene.
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Early uses

In the 19th and early-20th centuries,
benzene was used as an after-shave lotion
because of its pleasant smell. Prior to the
1920s, benzene was used as an industrial
solvent. To decaffeinate coffee
 Later benzene was used to improve the antiknock in gasoline.
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Benzene is an AROMATIC Compound

The term 'aromatic' was assigned before the
physical mechanism determining
aromaticity was discovered, and was
derived from the fact that many of the
compounds have a sweet scent.
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Benzene
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Tylenol and Advil
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Toluene

When a methyl group is attached to a
benzene ring, the whole structure is referred
to as toluene.
This is the #1 Carbon
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Naming Compounds Containing Toluene
toluene
2 chloro-toluene
2,3 dichloro-toluene
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2,4,6-trinitrotoluene
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Phenyl Groups
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Petroleum

This is a mixture of many compounds taken
out of the earth and separated into purer
compounds by means of a distillation tower.
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Figure 20.7: Benzene C6H6.
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Figure 20.8: Shorthand notation for benzene rings.
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Figure 20.10:
Names of
some
common
monosubstitut
ed benzenes.
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Figure 20.5: Energy sources used in the United States.
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Figure 20.6: Ball-and-stick model of ethylene.
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Figure 20.13:
Some carboxylic
acids.
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Table 20.5
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What is an Alcohol?

Alcohols: Contain the hydroxyl functional
group, –OH which replaces an –H in the
alkane.
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How to name Alcohols

Alcohols are named by replacing the “-e”
ending of the alkane with a “-ol” ending.
• methane, CH4, gives methanol, CH3OH
• ethane, C2H6, gives ethanol, C2H5OH
• Propane,
, gives 2-propanol,
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Organic Acids

Organic Acids Contain the carboxyl
Functional Group, –COOH
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What is a Keytone?

Ketones: Have the carbonyl functional
group bonded between two hydrocarbon
units.
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Naming Keytones

Ketones are named by replacing the -e
ending of the alkane with the -one ending
and prefixing the name with the number of
the carbonyl carbon
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Aldehydes
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Figure 20.9: The bonding in the benzene ring is a combination of different Lewis structures.
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