chemphys unit 7: organic chemistry
TRANSCRIPT
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