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Chapter 9 notes.notebook
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Jan 49:52 AM
ORGANIC CHEMISTRY the study of compounds of carbon
Jan 61:29 PM
Chapter 9: Hydrocarbons
Organic Compounds =
Molecular compounds
of carbon.
Hydrocarbons =
Compounds that are
formed from carbon
and hydrogen. nonpolar molecules. insoluble in water. low intermolecular forces, thus these
substances have very low melting and boiling points, in relation to their mass. will burn in oxygen to form carbon dioxide and
water.
Chapter 9 notes.notebook
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Apr 301:24 PM
Origin of Fossil Fuels:
1. Coal
2. Petroleum
3. Natural Gas
Apr 301:24 PM
Organic compounds can be represented in 3 ways:
1. Complete Structural Diagram
2. Condensed Structural Diagram
3. Line Structural Diagram
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Apr 301:26 PM
Example: Draw the 3 forms for C5H12
Nov 187:08 PM
hydrocarbons hydrocarbon derivatives
aliphatic aromatic
alkanes alkenes alkynes
Organic Chemistry
Contains other atoms such as O, Cl, Br, & N
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1) Aliphatic hydrocarbons carbon atoms arranged in straight or
branched chains (can also form ring structures, although we will focus on the straight and branched chains).
a) Alkanes contain only single carboncarbon bonds, that is, the carbon atoms share only one pair of electrons.b) Alkenes contain one or more double
carboncarbon bonds, that is, the carbons share 2 pairs of electrons.c) Alkynes contain one or more triple carbon
carbon bonds.
2) Aromatic hydrocarbons contain a benzene ring.
Aliphatic hydrocarbons can be divided into alkanes, alkenes and alkynes.
Jan 410:06 AM
9.2 : Representing HydrocarbonsThe Carbon Atom (C)
Carbon has unique bonding properties that allow for millions of different organic molecules to exist.
These properties are:
carbon has 4 bonding electrons
carbon can single, double or triple bond with itself
carbon atoms can bond together to form a variety of geometrical structures including chains, spheres, rings and tubesThere are three ways to draw structural diagrams for organic compounds.1. Complete structural diagram
2. Condensed structural diagram
3. Line structural diagram
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Jan 412:32 PM
Hydrocarbon prefixes:
1C = meth2C = eth3C = prop4C = but5C = pent
6C = hex7C = hept8C = oct9C = non10C = dec
Naming Hydrocarbons:* first part indicates the number of carbons* second part indicates family name
Jan 411:35 AM
Alkanes* nonpolar* single covalent bonds* low boiling points* low solubility in H2O* simplest form of hydrocarbon * aliphatic hydrocarbons (form chains and nonaromatic rings)* saturated (each carbon is bonded to a maximum number of atoms)* ending is ane****** general formula is CnH2n+2
1. METHANE is the simplest alkane1. it is a gas at STP2. major component of natural gas3. formula is CH4
2. ETHANE is the simplest alkane containing a carbon to carbon bond1. formula is C2H6
CH3CH2CH2CH3Ex:
hexane
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Nov 187:41 PM
Continuous Chain Alkanes p.333
Continuous chain alkanes contain any number of carbon atoms in a straight chain (this does not mean linear).
*****Memorize table 9.2 MethaneEthanePropaneButanePentaneHexaneHeptaneOctaneNonaneDecane
Nov 187:44 PM
If an atom(s) takes the place of a hydrogen atom on a parent hydrocarbon molecule, that atom is called a SUBSTITUENT. Common substituents are halogens or groups of atoms containing hydrogen, oxygen, nitrogen, sulfur, and phosphorus.
A hydrocarbon substituent is called an ALKYL GROUP. They are named by removing the ane ending from the parent hydrocarbon and adding the ending yl.
An alkane with one or more alkyl groups is called a BRANCHED CHAIN ALKANE.
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Branched Alkanes
branches are any group of atoms that are not part of the main structure (parent chain)
*the longest continuous chain of carbon atoms
C C C C
C
C C C C
C
C C C
C
C
*These hydrocarbon substituents are called ALKYL GROUPS.
Jan 412:48 PM
To Name:
C C C C
C
Rules for naming branched chain alkanes p.335:
1. Find the longest continuous chain and name it. (This is the parent chain).
2. Number the carbons. Start with the end with the most alkyl groups
3. Name alkyl groups4. Use prefixes for appearances of a group more than once (di,
tri, tetra, penta)5. List the names of the alkyl groups alphabetically. NOTE the
prefixes di, tri, etc. are ignored when alphabetizing.6. Use punctuation: 7. commas separate numbers from each other8. hyphens separate numbers and words9. write last alkyl and parent name together.
10. {Problems: naming alkanes, drawing alkanes, and invalid naming of alkanes}
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1. Identify the parent chain2. Number the carbons from the end closest to the branch3. Identify the location and branch(es) (alkyl group).4. Name the compound using IUPAC format
(# of carbons) (branch name)(parent chain name)*Branches are listed in alphabetical order*# prefixes are used for multiple, similar branches
C C C C
C
C C C
C
C
Jan 62:23 PM
Draw a complete structural, condensed structural, and line structure for 3 ethyl 2 methylhexane
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May 252:00 PM
C C C CC CCC
C
C
C
3,3,4 triethyl 6,7 dimethyl 4propyldecane
Name!
May 79:53 AM
DO EXAMPLES
BUILD FIRST ONE WITH CARBONS
There are 3 isomers
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Cycloalkanes single bonds in closed rings
C
C C
Cyclic hydrocarbons
*Same as regular but add cyclo before the parent chain.* Number the branches in a way to get the lowest total.
IF a cycloalkane has only one substituent ,do not use 1.
RULES:
Jan 62:30 PM
cyclohexane
1ethyl2,3dimethylcyclohexane
1,3diethyl2methylcyclopentane
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Reactions of Alkanes :
1) COMPLETE COMBUSTION• occurs if enough oxygen is present• a blue flame indicates complete combustion• a hydrocarbon that undergoes complete combustion always
produces carbon dioxide and water> {problem – write balanced equations for the complete
combustion of a hydrocarbon}
Nov 188:12 PM
2) INCOMPLETE COMBUSTION• occurs when there is not enough oxygen present• indicated by a yellow flame• products are still carbon dioxide and water BUT also
include CO and C> {problem – Write balanced equations for the incomplete
combustion of a hydrocarbon – NOTE: more than one answer is possible}
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May 123:00 PM
C125 incomplete combustion
Jan 611:44 AM
9.3 Alkenes* contains one or more DOUBLE BONDS!* normally lower boiling points (than similar sized alkanes)* low solubility in water* nonpolar so dissolve in nonpolar solvents.* aliphatic hydrocarbons (form chains and nonaromatic rings)*unsaturated hydrocarbons because at least two carbons are bonded to fewer than four atoms
*can form cis or trans isomers around the double bond (discuss later)
*******general formula CnH2n
C C C C C C
UnsaturatedSaturated
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Alkynes* contains one or more TRIPLE BONDS!!!* not plentiful in nature* aliphatic hydrocarbons (forms chains and nonaromatic rings)* unsaturated hydrocarbons because at least two carbons are bonded to fewer than four atoms* nonpolar* general formula CnH2n2
Jan 62:33 PM
Ex:
Naming:* the longest parent chain MUST contain the double or triple bond* number the carbons from the end closest to the multiple bond (ignore the branches)* the name of the parent chain must be preceded by a # indicating the position of the multiple bond
C C C
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C C CCCC
C
C
C
Jan 62:44 PM
4 ethyl 5,6 dimethyl 2 heptyne
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Jan 118:58 AM
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Jan 168:52 AM
General Rules of Cis/Trans Isomers:
• each carbon involved in the double bond must be attached to two different groups• in a cis isomer, the two larger groups must be on the same side of the double bond• in a trans isomer the two larger groups must be on the opposite side of the double bond• Like all isomers, cis and trans isomers have different physical and chemical properties
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Jan 1611:17 AM
Draw the cis or trans isomer:
a) cis3octene b) trans2butene
c) cis3nonene d) trans2hexene
e) cis2heptene f) trans3decene(line structure)
Jan 1012:38 PM
Cycloalkenes
CH3
CH3
CH3
CH2CH3
*the carbons must be numbered starting at the double bond (C1 and C2)
Cyclic hydrocarbons cont...
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Jan 152:46 PM
Cycloalkynes* Because triple bonds are linear, Ex: CC CC, cycloalkynes usually do not exist because they are usually highly strained and can only exist when the number of carbon atoms in the ring is great enough to provide some flexibility to make up for the linear geometry.
Ex: Smallest possible alkyne is octyne.
Jan 2112:00 PM
Aromatic Hydrocarbons
Aromatic Hydrocarbons- a hydrocarbon based on the aromatic benzene group.The molecular formula of benzene is C6H6.
Kekule:
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Jan 2112:21 PM
Correct
Jan 2112:07 PM
-the electrons that form the double bond in benzene are spread out and shared over the whole molecule-these electrons are called delocalized electrons
-6 identical bonds-molecules with this type of special electron sharing are called aromatic compounds-benzene is the simplest aromatic compound-almost all aromatic compounds contain one or more benzene rings
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Jan 2112:12 PM
Naming:-number the carbons in the benzene ring. If more than one branch is attached to the ring, start numbering at the carbon with the highest priority (most complex) group**See page 361 Problem Tip
Jan 2112:14 PM
http://chemed.chem.purdue.edu/genchem/topicreview/bp/1organic/graphics/34b.gif
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Jan 221:31 PM
Review Question
Name this compound.
Jan 1210:35 PM
General Formulas
Alkanes
Alkenes
Alkynes
CycloAlkanes
Cycloalkenes
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Jan 218:37 AM
ALKYL HALIDES
* An alkane in which one or more hydrogen atoms have been replaced with halogen atoms (F, Cl, Br, or I)
Prefixes for halogens: fluoro chloro bromo iodo
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Br I
Cl
C C C C C
I
F
F
8chloro3,4difluoro3iodo4nonene
Name/Draw:
May 282:31 PM
Page 391 #12,13
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Examples:
Jan 410:16 AM
FAMILIESFamily Name General Formula Example
Alkane
Alkene
Alkyne
Aromatic
Organic Halide
Alcohol
Carboxylic Acid
Aldehyde
Ketone
Ester
C C
.
PropaneCH3CH2CH3
C CPropene
CH2=CHCH3
C CPropyneCHCCH3
Methyl benzeneCH3
RXChloropropane
CH3CH2CH2Cl
ROHPropanol
CH3CH2CH2OH
R(H) C OHO Propanoic Acid
CH3CH2COH
O
R(H) C HO Propanal
CH3CH2CHO
R1 C R2
O Propanone
CH3CCH3
O
R1(H) C O R2
O Methyl ethanoate
CH3COCH3
O
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Jan 191:05 PM
Alcohols an organic compound that contains the hydroxyl functional group (a reactive group of bonded atoms)
ROH
Naming:* the parent must contain the carbon attached to the hydroxyl group*drop the e at the end of the parent and add ol* indicate the carbon # that the OH is bonded to* branches named in the same way as before
Jun 58:42 AM
C C C C C
I
F
FOH
C C C C
C
OH
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Jun 58:45 AM
OH
OH
1,2dichloro4octanol
Jan 221:45 PM
Page 388 #8a,b,c,e#9 a,b,d,e
* Omit primary, secondary, tertiary
Homework!
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Aldehydes
* a carbonyl group attached at the end of a carbon chain
* RCHO* al ending
Carbonyl group C=O
Jan 191:08 PM
4bromo2,2dimethylbutanal
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Page 403 #28 a,d #29 a,c
Jan 191:05 PM
Ketones* a carbonyl group on a central carbon of a hydrocarbon chain
* RCR
=O
* one ending
Carbonyl group C=O
*You must indicate the #of the carbon that the carbonyl group is on
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3,3,4trimethyl2pentanone
4chiaro3ethyl2hexatone
Jan 2312:30 PM
Page 403 #28 b,c,e #29 b
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Carboxylic Acids
* a carboxyl group (COOH) attached at the end of a carbon chain
* RCOOH
* oic acid ending
Jan 201:25 PM
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Page 406 #32,33
Jan 410:16 AM
FAMILIESFamily Name General Formula Example
Alkane
Alkene
Alkyne
Aromatic
Organic Halide
Alcohol
Carboxylic Acid
Aldehyde
Ketone
Ester
C C
.
PropaneCH3CH2CH3
C CPropene
CH2=CHCH3
C CPropyne
CHCCH3
Methyl benzeneCH3
RXChloropropane
CH3CH2CH2Cl
ROHPropanol
CH3CH2CH2OH
Propanoic Acid CH3CH2COH
O
Propanal
CH3CH2CHO
R1 C R2
O Propanone
CH3CCH3
O
R1 C O R2
O Methyl Ethanoate
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Nov 188:07 PM
Note: alkanes are often found a STRUCTURAL ISOMERS, that is, the
compounds have the same molecular formula, but have different molecular structures.
~~Structural isomers differ in their physical and chemical properties. Generally, the more branched the hydrocarbon the lower the melting point compared with its other structural isomers.