10 10-1 © 2003 Thomson Learning, Inc. All rights reserved General, Organic, and Biochemistry, 7e...

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10-1© 2003 Thomson Learning, Inc.All rights reserved

General, Organic, and General, Organic, and Biochemistry, 7eBiochemistry, 7e

Bettelheim,Bettelheim,

Brown, and MarchBrown, and March

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Chapter 10Chapter 10

Organic ChemistryOrganic Chemistry

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Organic ChemistryOrganic Chemistry• Organic chemistry:Organic chemistry: the study of the compounds

of carbon• organic compounds are made up of carbon and only a

few other elements• chief among these are hydrogen, oxygen, and nitrogen• also present are sulfur, phosphorus, and a halogen

(fluorine, chlorine, bromine, or iodine)

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Organic ChemistryOrganic Chemistry• Why is organic chemistry a separate discipline

within chemistry?• historical:historical: scientists at one time believed that a

“vital force” present in living organisms was necessary to produce an organic compound• the experiment of Wöhler in 1828 was the first in a

series of experiments that led to the demise of the vital force theory

NH4Cl AgNCO H2N-C-NH2

OAgCl+ heat +

Ammoniumchloride

Silvercyanate

Urea Silverchloride

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Organic ChemistryOrganic Chemistry• The sheer number of organic compoundsThe sheer number of organic compounds

• chemists have discovered or made over 10 million organic compounds and an estimated 100,000 new ones are discovered or made each year

• by comparison, chemists have discovered or made an estimated 1.7 million inorganic compounds

• thus, approximately 85% of all known compounds are organic

• The link to biochemistryThe link to biochemistry• carbohydrates, lipids, proteins, enzymes, nucleic acids,

hormones, vitamins, and almost all other chemicals in living systems are organic compounds

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Organic ChemistryOrganic Chemistry• a comparison of organic and inorganic compounds

Organic Compounds Inorganic Compounds

Bonding is almost entirely covalentMay be gases, liquids, or solidswith low melting points (lessthan 360°C)Most are insoluble in waterMost are soluble in organic solventssuch as diethyl ether, toluene, and dichloromethaneAqueous solutions do notconduct electricityAlmost all burn

Reactions are usually slow

Most have ionic bondsMost are solids with high melting points

Many are soluble in waterAlmost all are insoluble in organic solvents

Aqueous solutions conductelectricityVery few burn

Reactions are often very fast

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Organic StructureOrganic Structure• structural formula:structural formula: shows the atoms present in a

molecule as well as the bonds that connect them• VSEPR model:VSEPR model: the most common bond angles are

109.5°, 120°, and 180°

H-C-C-H

H

H H

H H

HC C

H

HH-C C-H

H-C-O-H

H

H

HC O

HH-C-N-HH

HH

HN

H HC

H-C-C-Cl

H

H H

H

Ethane(bond angles

109.5°)

Ethylene(bond angles

120°)

Acetylene(bond angles

180°)

Methanol(bond angles

109.5°)

Formaldehyde(bond angles

120°)

Methanamine(bond angles

109.5°)

Methyleneimine(bond angles 120°)

Chloroethane(bond angles

109.5°)

::

::::

::

:

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Organic StructureOrganic Structure• Among neutral (uncharged) organic compounds

• carbon: carbon: four covalent bonds and no unshared pairs of electrons

• hydrogen:hydrogen: one covalent bond and no unshared pairs of electrons

• nitrogen:nitrogen: three covalent bonds and one unshared pair of electrons

• oxygen:oxygen: two covalent bonds and two unshared pairs of electrons

• a halogen:a halogen: one covalent bond and three unshared pairs of electrons

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Functional GroupsFunctional Groups• Functional group:Functional group: a part of an organic molecule

that undergoes chemical reaction• Functional groups are important because

• they undergo the same types of chemical reactions no matter in which molecule they are found

• to a large measure they determine the chemical and physical properties of a molecule

• they are the units by which we divide organic compounds into families

• they provide the basis on which we derive names for organic compounds

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Functional GroupsFunctional Groups• Five important functional groups

-OH

-NH2

-C-HO

-C-O

CH3CH2OH

CH3CH2NH2

CH3CHO

CH3CCH3

O

CH3COHO

-C-OHO

Example

Alcohol

Amine

Aldehyde

Ketone

Carboxylic acid

Ethanol

Ethanamine

Ethanal

Acetone

Acetic acid

NameFamilyFunctionalgroup

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AlcoholsAlcohols• Alcohol:Alcohol: contains an OH (hydroxyl) group bonded

to a tetrahedral carbon atom

• may be primary (1°), secondary (2°), or tertiary (3°)

CH3-C-OH

H

HCH3-C-OH

CH3

HCH3-C-OH

CH3

CH3

A 1° alcohol A 3° alcoholA 2° alcohol

R-C-O-HR

RCH3CH2OH

H

HH

HH-C-C-O-H

Structuralformula

Functional group(R = H or carbon

goup

Condensedstructuralformula

::

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AlcoholsAlcohols• Problem:Problem: draw Lewis structures and condensed

structural formulas for the two alcohols of molecular formula C3H8O

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AlcoholsAlcohols• Problem:Problem: draw Lewis structures and condensed

structural formulas for the two alcohols of molecular formula C3H8O

• Solution:Solution:

CH3CH2CH2OH

CH3CHCH3

OH

H-C-C-C-O-HH

H

H

H

H

H

C-C-C-HH

H

O

HH

H

H

H

A primary alcohol

A secondary alcohol

Lewis stucturesCondensed structural

formulas

::

::

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AminesAmines• Amine:Amine: a compound containing an amino groupamino group

• the amino group may be primary (1°), secondary (2°), or tertiary (3°)

CH3NH

CH3

CH3NH2 CH3NCH3

CH3

(CH3)3N(CH3)2NH

Methylamine(a 1° amine)

Dimethylamine(a 2° amine)

Trimethylamine(a 3° amine)

or or

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AminesAmines• Problem:Problem: draw condensed structural formulas for the

two primary amines of molecular formula C3H9N

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AminesAmines• Problem:Problem: draw condensed structural formulas for the

two primary amines of molecular formula C3H9N

• Solution:Solution:

CH3CH2CH2NH2C-C-C-NH2 C-C-C

NH2

CH3CHCH3

NH2

The three carbons may be bonded to nitrogen

in two ways

Add seven hydrogens to give eachcarbon four bonds and give the

correct molecular formula

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Aldehydes and KetonesAldehydes and Ketones• Both contain a C=O (carbonyl) groupC=O (carbonyl) group

• aldehyde:aldehyde: contains a carbonyl group bonded to a hydrogen; in formaldehyde, the simplest aldehyde, the carbonyl group is bonded to two hydrogens

• ketone:ketone: contains a carbonyl group bonded to two carbon atoms

CH3CHO O

CH3CCH3C-C-HR

R

ROC-C-C

O

RR

RR

R R

Functionalgroup

Functionalgroup

Acetaldehyde(an aldehyde)

Acetone(a ketone)

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Aldehydes and KetonesAldehydes and Ketones• Problem:Problem: draw condensed structural formulas

for the two aldehydes of molecular formula C4H8O

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Aldehydes and KetonesAldehydes and Ketones• Problem:Problem: draw condensed structural formulas

for the two aldehydes of molecular formula C4H8O

• Solution:Solution: • first draw the functional group of an aldehyde

and add the remaining three carbons; these may be bonded in two ways.

• then add the seven hydrogens necessary to complete the four bonds of each carbon.

CH3CH2CH2CH

OCH3CHCH

O

CH3

CH3CH2CH2CHO CH3CHCHO

CH3

or or

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Carboxylic AcidsCarboxylic Acids• Carboxylic acid:Carboxylic acid: a compound containing a compound containing a

-COOH (carboxyl: carbcarbonyl + hydroxyloxyl) group • in a condensed structural formula, a carboxyl

group may also be written -CO2H.RCOHO

CH3COHO

Functionalgroup

Acetic acid(a carboxylic acid)

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Carboxylic AcidsCarboxylic Acids• Problem:Problem: draw a condensed structural formula

for the single carboxylic acid of molecular formula C3H6O2

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Carboxylic AcidsCarboxylic Acids• Problem:Problem: draw a condensed structural formula

for the single carboxylic acid of molecular formula C3H6O2

• Solution:Solution: the only way the carbon atoms can be written is three in a chain; the -COOH group must be on an end carbon of the chain

CH3CH2COOHCH3CH2COH

Oor

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Chapter 10 Organic ChemistryChapter 10 Organic Chemistry

End End

Chapter 10Chapter 10

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