ChemPhys UNIT 7: Organic Chemistry

Chemistry & Physics

UNIT 7: ORGANIC CHEMISTRY

Chemistry

Periodic table

Chemical reaction

Matter

Atoms

Chemical bonding

Electrolytes

Hydrocarbons

Organic chemistry

Today

• Introduction

– Organic vs. Inorganic

– Formulas

– Isomerism

• Alkanes

– Naming

• Alkenes and alkynes

– Naming

– Geometric isomers

– Biologically important alkenes

PreQuiz

1. Which of the following is an organic substance?

a) Water; b) Salt; c) Diamond

2. What type of bonding is usually found in organic compounds?

a) Covalent bonding; b) Ionic bonding; c) Hydrogen bonding

3. The molecular and emperical formula of ethane are _____?

a) C2H6 / C2H6; b) C2H6 / CH3; c) C2H6 / C4H12

4. HC≡CH is part of the family of the _____?

a) Alkanes; b) Alkenes; c) Alkynes

5. Alkanes react primarily by _____?

a) Neutralization; b) Substitution; c) Addition

6. Haloalkanes are often used as _____?

a) Disinfectant; b) Anestetics; c) Hormones

7. β-carotene is a(n)_____?

a) Plant hormone; b) Aromatic ; c) Precursor of Vitamin A

8. Cis- and trans-2-butene are examples of _____?

a) cycloalkenes; b) geometric isomers; c) lazy chemicals

9. What is the name of the following compound:

a) 3-methyl-1-butene; b) 2-methyl-3-butyne; c) 3-methyl-1-butane

Organic chemistry

BONDING

FORMULAS

ISOMERS

Organic materials

ORGANIC MATTER

Chemistry of life

Sackheim’s Chemistry: Chapter 14

Organic vs. inorganic

Organic Inorganic

Based on C Not based on C

Nonelectrolyte Electrolyte (acids, bases, salts)

Covalent bonding Ionic bonding

Low boiling and melting point High boiling and melting point

Soluble in nonpolar solvents Soluble in polar solvents (water)

Complex structure Simple structure

Millions of compounds Thousands of compounds

Sackheim’s Chemistry: Chapter 14

UniqueCovalent bonds with itselfCovalent bonds with others

C-C bonds

• Carbon-Carbon (C-C) bond

– Unique: covalent bonds with other C atoms

– 4 valence (outer) electrons: maximum of 4 covalent bonds

Sackheim’s Chemistry: Chapter 14

Covalent bonds“Sharing electrons”

C-C compounds

GraphiteGood electrical

conduction

DiamondHardest natural

substance

Fullerene Nanotube

Sackheim’s Chemistry: Chapter 14

Create Carbon

C-H bonds

• Carbon-Hydrogen (C-H) bond

– Each carbon atom forms 4 bonds: octet rule

– Each hydrogen atom form 1 bond

– Alkane: single bond

– Alkene: double bond

– Alkyne: triple bondSackheim’s Chemistry: Chapter 14

Alkane

Alkene

Alkyne

Other C bonds

• Carbon-Oxygen (C-O) and Carbon-Fluor (C-F) bond

– Each carbon atom forms 4 bonds: octet rule

– Each oxygen atom forms 2 bonds (double bond): octet rule

– Each fluor atom forms 1 bond: octet rule

Sackheim’s Chemistry: Chapter 14

Formulas

• Definition

– Group of symbols that represent the elements present in a substance

• Molecular formula

– Written formula

– Presents actual number of atoms in the substance

– Cannot tell the structure

• Structural formula

– 2D view of structure

– Presents connection between atoms

Sackheim’s Chemistry: Chapter 14

“ISOMERS”

Isomerism

• Isomers

– Same molecular structure

– Different structural formula: different properties

Boiling point = 78 °Cliquid

-25 °Cgas

Sackheim’s Chemistry: Chapter 14

Nomenclature

• Naming of chemical compounds

– Via IUPAC system

Carbonatoms

Alkanes Alkenes Alkynes

1 CH4: methane - -

2 C2H6: ethane C2H4: ethene C2H2: ethyne

3 C3H8: propane C3H6: propene C3H4: propyne

4 C4H10: butane C4H8: butene C4H6: butyne

5 C5H12: pentane C5H10: pentene C5H8: pentyne

6 C6H14: hexane C6H12: hexene C6H10: hexyne

Sackheim’s Chemistry: Chapter 15,16

Saturated hydrocarbons

NAMES

STRUCTURE

PROPERTIES

USE

Source of hydrocarbons

Sackheim’s Chemistry: Chapter 15

Natural gas

Petroleum

Alkanes

• Hydrocarbons = compounds with C and H only

– SATURATED (alkanes): single bonds

Sackheim’s Chemistry: Chapter 15

Methane: (CH4) General formula: CnH2n+2

Free rotation vs. isomers

• Same compounds

– Rotation of C-C single bonds

– All structures are the same

– C4H10: butane

• Isomer

– Same molecular formula

– Different structural formula

– C4H10: iso-butane

Sackheim’s Chemistry: Chapter 15

Lazy scientists

• Condensed structural formulas

CH3-CH2-CH2-CH3

CH3CH2CH2CH3

CH3(CH2)2CH3 deg

ree

of

lazi

nes

s

Sackheim’s Chemistry: Chapter 15

Nomenclature alkanes

• IUPAC system

1. Search for longest carbon chain (head chain) and name it

2. Number the carbon atoms of the head chain

3. Search for side groups that are not part of head chain andname them

Carbonatoms

Head chain Side group

1 CH4: methane –CH3: methyl

2 C2H6: ethane –C2H5: ethyl

3 C3H8: propane –C3H7: propyl

4 C4H10: butane –C4H9: butyl

5 C5H12: pentane –C5H11: pentyl

6 C6H14: hexane –C6H13: hexyl

7 C7H16: heptane –C7H15: heptyl

8 C8H18: octane –C8H17: octyl

9 C9H20: nonane –C9H19: nonyl

10 C10H22: decane –C10H21: decyl

Sackheim’s Chemistry: Chapter 15

Practice (1)

• IUPAC system

1. Search for longest carbon chain (head chain) and name it

2. Number the carbon atoms of the head chain

3. Search for side groups that are not part of head chain andname them

Butane

2-methylbutane

Octane

2,3-dimethyl-4-ethyloctane

1 2 3 4

8 7 6 5 4 3 2 1

Sackheim’s Chemistry: Chapter 15

Practice (2)

2-ethyl-3-chloro-4-methylheptane

1 2 3 4 5 6 7

Sackheim’s Chemistry: Chapter 15

Cycloalkanes

• Shape of ring

– Prefix: cyclo-

– Structures can be abbreviated with geometric shape

Sackheim’s Chemistry: Chapter 15

Properties

Carbonatoms

Formula andname

Boilingpoint (°C)

State of matter

1 CH4: methane -162 Gas

2 C2H6: ethane -89 Gas

3 C3H8: propane -42 Gas

4 C4H10: butane 0 Gas

5 C5H12: pentane 36 Liquid

6 C6H14: hexane 69 Liquid

7 C7H16: heptane 98 Liquid

8 C8H18: octane 126 Liquid

9 C9H20: nonane 151 Liquid

10 C10H22: decane 174 Liquid

Sackheim’s Chemistry: Chapter 15

Combustion

• Complete combustion

– Alkanes react with oxygen to produce carbon dioxide, water and energy

• Incomplete combustion

– Alkanes produce also carbon monoxide (poisoning) due to insufficient O2

Sackheim’s Chemistry: Chapter 15

Halogenation

• Substitution

– Alkanes react with halogens (F2, Cl2, Br2, I2)

– Halogen (F, Cl, Br, I) replaces hydrogen (H)

– Product: haloalkane

bromomethane

chloromethane dibromomethanetriiodomethane

Sackheim’s Chemistry: Chapter 15

substitution

Anesthetics

Sackheim’s Chemistry: Chapter 15

cyclopropane chloroethane

“chloral hydrate” “halothane”

Unsaturated hydrocarbons

NAMES

STRUCTURE

PROPERTIES

USE

Alkenes

• Hydrocarbons = compounds with C and H only

– SATURATED (alkanes): single bonds

– UNSATURATED (alkenes or alkynes): double or triple bonds

Sackheim’s Chemistry: Chapter 16

Ethene: (C2H4) General formula: CnH2n

Cycloalkenes

• Shape of ring

– Prefix: cyclo-

– Structures can be abbreviated with geometric shape

Sackheim’s Chemistry: Chapter 16

Alkynes

• Hydrocarbons = compounds with C and H only

– SATURATED (alkanes): single bonds

– UNSATURATED (alkenes or alkynes): double or triple bonds

Sackheim’s Chemistry: Chapter 16

Ethyne: (C2H2) General formula: CnH2n-2

Nomenclature alkenes and alkynes

• IUPAC system

1. Search for longest carbon chain (head chain) with double/triple bond and name it

2. Number the carbon atoms of the head chain and give lowest numberpossible to double bond

3. Search for side groups that are not part of head chain and name them

Carbonatoms

Alkanes Alkenes Alkynes

1 CH4: methane - -

2 C2H6: ethane C2H4: ethene C2H2: ethyne

3 C3H8: propane C3H6: propene C3H4: propyne

Sackheim’s Chemistry: Chapter 16

Practice (3)

• IUPAC system

1. Search for longest carbon chain (head chain) with double/triple bond and name it

2. Number the carbon atoms of the head chain and give lowest numberpossible to double bond

3. Search for side groups that are not part of head chain and name them

Sackheim’s Chemistry: Chapter 16

Butene

1-butene

3-methyl-1-butene

4 3 2 1

Cyclohexene

1-cyclohexene

3-methyl-1-cyclohexene

1 2

5 4

6 3

Practice (4)

• IUPAC system

1. Search for longest carbon chain (head chain) with double/triple bond and name it

2. Number the carbon atoms of the head chain and give lowest numberpossible to double bond

3. Search for side groups that are not part of head chain and name them

Sackheim’s Chemistry: Chapter 16

Octyne

2-octyne

4,4-dibromo-5-ethyl-6-methyl-2-octyne

1 2 3 4 5 6 7 8

Practice (5)

• IUPAC system

1. Search for longest carbon chain (head chain) with double/triple bond and name it

2. Number the carbon atoms of the head chain and give lowest numberpossible to double bond

3. Search for side groups that are not part of head chain and name them

Sackheim’s Chemistry: Chapter 16

3,4-diethyl-2-hexene

1 2 3 4 5 6

Addition

• Reactions with alkenes/alkynes

– Addition: from unsaturated to saturated

Sackheim’s Chemistry: Chapter 16

hydrogenation

halogenation

Geometric isomers

no free rotation

“Same molecular formula but different structural formula”

same side opposite side

4 °C 0 °C

Sackheim’s Chemistry: Chapter 16

Biological importance

• Ethene

– Plant hormone (ripening fruits)

• Linoleic acid

– Found in nuts and oils (essential for body)

• Arachidonic acid

– Found in meat, eggs, diary (essential for body)

• β-carotene

– In fruits and vegetables (precursor vitamin A)

• Vitamin A

– From β-carotene (essential for body)

• Isoprene

– Present in natural rubber (industrial use) Sackheim’s Chemistry: Chapter 16

Aromatics

• Unsaturated hydrocarbons

– Pleasant odor

– Special ring-shaped structure

Sackheim’s Chemistry: Chapter 16

Benzene derivatives

Toluene

XylenePhenanthrene

TNT

Sackheim’s Chemistry: Chapter 16

PostQuiz

1. Which of the following is an organic substance?

a) Water; b) Salt; c) Diamond

2. What type of bonding is usually found in organic compounds?

a) Covalent bonding; b) Ionic bonding; c) Hydrogen bonding

3. The molecular and emperical formula of ethane are _____?

a) C2H6 / C2H6; b) C2H6 / CH3; c) C2H6 / C4H12

4. HC≡CH is part of the family of the _____?

a) Alkanes; b) Alkenes; c) Alkynes

5. Alkanes react primarily by _____?

a) Neutralization; b) Substitution; c) Addition

6. Haloalkanes are often used as _____?

a) Disinfectant; b) Anestetics; c) Hormones

7. β-carotene is a(n)_____?

a) Plant hormone; b) Aromatic ; c) Precursor of Vitamin A

8. Cis- and trans-2-butene are examples of _____?

a) cycloalkenes; b) geometric isomers; c) lazy chemicals

9. What is the name of the following compound:

a) 3-methyl-1-butene; b) 2-methyl-3-butyne; c) 3-methyl-1-butane

The End