what is meant by the term organic? 1. page 2 2 characteristics of organic compounds formed as a...
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Characteristics of organic compounds
• Formed as a result almost exclusively of covalent bonding
• Generally nonpolar Generally insoluble in water– usually soluble in nonpolar solvents (other organic
compounds)• Non-electrolytes except organic acids which are
weak electrolytes• Have low melting points (due to weak
intermolecular forces that hold them together)– The great number of carbons leads to a higher melting
point.3
Characteristics of organic compounds, (continued)
• Have slower reaction rates than inorganic compounds– covalent bonds within organic molecules are strong– activation energies are high– catalysts are often used to increase reaction rates
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• Hydrocarbons– Definition - compounds composed of only
hydrogen and carbon– There are so many hydrocarbons found in nature;
nearly impossible to study all! They are grouped in Homologous series.
– Homologous series - group of organic compounds with similar properties and related structures (differ from each other by CH3)
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• Aliphatic - hydrocarbon chains– Saturated
• Definition - has no bonds that can be broken to add extra hydrogen
• called Alkanes– family of hydrocarbons with all single bonds– general formula CnH2n+2
– named with suffix "ANE“– Table P – Organic Prefixes– As the number of carbons increases, the boiling point
increases.
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TAKE OUT PAPER AND DRAW PLEASE
• Name and draw the first ten Alkanes– Go to table P and look at the prefix for the
number of carbons• 1 carbon is Meth
– All alkanes end in ‘ane’» ‘meth’ and ‘ane’» Methane
• 2 carbons is Eth– All alkanes end in ‘ane’
» ‘eth’ and ‘ane’» Ethane
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– Unsaturated - has double or triple bonds that can be broken to add more hydrogen
• Alkenes– family of hydrocarbons with at least one double bond– general formula CnH2n
– named with suffix "ENE“– Starts with Ethene.
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AlkenesTAKE OUT PAPER AND DRAW PLEASE
• Draw the first nine Alkenes– Go to table P and look at the prefix for the
number of carbons• 2 carbons is Eth
– All alkenes end in ‘ene’» ‘eth’ and ‘ene’» Ethene
• 3 carbons is Prop– All alkenes end in ‘ene’
» ‘prop’ and ‘ene’» Propene
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Alkenes TAKE OUT PAPER AND DRAW PLEASE
• Draw the first nine Alkenes– Go to table P and look at the prefix for the
number of carbons• 4 carbons is But
– All alkenes end in ‘ene’» ‘but’ and ‘ene’» Butene
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Alkynes
• Alkynes– family of hydrocarbons with one triple bond– general formula CnH2n-2
– named with suffix "YNE“– Starts with Ethyne.
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Alkynes
• Draw the first nine Alkynes– Go to table P and look at the prefix for the
number of carbons• 2 carbons is Eth
– All alkenes end in ‘yne’» ‘eth’ and ‘yne’» Ethyne
• 3 carbons is Prop– All alkenes end in ‘yne’
» ‘prop’ and ‘yne’» Propyne
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The Benzene Series (Aromatic hydrocarbons)
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The benzene series consists of molecules which are cyclic in nature.The general formula is CnH2n-6.
Benzene HC
H C C HC6H6
H C C HCH
Although it appears that the structure has alternating double and single bonds, the bonding involves six identical bonds. A resonance structure is used to show structural formula of benzene.
H HC C
H C C H H C C H
H C C H H C C HC CH H
An abbreviated structural formula can be used in place of the above:
OR
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Toluene or Methylbenzene C7H8
HC
H C C CH3
H C C HCH
An abbreviated structural formula can be used in place of the above:
CH3 CH3
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• Rule 2: Assign numbers to each C atom in the longest chain, starting at the end with the attached group.
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• Rule 3: If more than one of the same types of group is attached to the main chain prefixes are used to identify the attached groups.
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• Rule 4: When naming alkenes or alkynes the carbon with the double/triple bond, the carbon number with the double/triple bond must be identified in the name.
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Different ways to represent one compound
• Molecular Formula• Structural Formula• Condensed Structural Formula• Ball-and-Stick Model• Space-Filling Model
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Molecular Formula
• Shows the kind and number of atoms in a compound.
• Example: CH4 or C2H6
• Tells us that there are carbon and hydrogen atoms. For methane, there are 4 hydrogens for 1 carbon atom.
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Structural Formula
• In addition, shows the bonding patterns and two-dimensional view.
• For example:
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Condensed Structural Formula
• Written structural formula• For example: Methane: CH4
• Ethane: CH3CH3
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Isomers
• Isomers: When a molecular formula can be represented by more than one structural arrangement
• Isomers have the same molecular formula, but different physical and chemical properties.
• As the # of carbon atoms increases, so does the # of possible isomers
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Isomer Practice
•Draw 3 Isomers for 5 and 6 carbon Alkanes.•Be sure you have the correct number of hydrogens.
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Functional Groups
• Atoms or groups of atoms that replace hydrogen atoms in a hydrocarbon.
• This will form new compounds?• They have distinct physical and chemical
properties.• There are 9 functional groups• All found on Table R!
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C, H and O• Alcohols (R-OH)
– ethanol, isopropyl alcohol, (rubbing alcohol)• Ethers (R-O-R)
– dimethyl ether (old anaesthetic)• Ketones
– acetone (nail polish remover)• Aldehydes (a ketone with at least one R = H)
– formaldehyde • Esters
– many fine odours• Carboxylic acids
– acetic acid• Carbohydrates
– (CH2O)n, glucose, starch, cellulose48
R
O
R
R
O
O
R
H3C O CH3
H3C
C
O
CH3
H3C
C
O
OH
H
CHOC
OH
C
H
OH
C
OH
H
C
OH
H
HOH2C
1. Halides• A Halogen (F, Cl, Br, or I) replaces a hydrogen on a
hydrocarbon.• Used as organic solvents• General Formula: R-X (X= Halogen & R= Alkyl group)• Add fluoro for F Designate the location of
• Chloro for Cl the halide with 1,2 etc• Bromo for Br• Iodo for I
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2-fluoropropane
2. AlcoholsOrganic compounds in which one or more hydrogen
atoms are replaced by an –OH group.-OH group is called a hydroxyl group.NOT A BASE!They are nonelectrolytes (Do not form ions in solution).Polar substancesGeneral Formula: R-OHNaming: Position of OH group must be assigned & -ANE
ending changes to –OL.
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Classification of AlcoholsThere are primary, secondary, and tertiary carbon
atoms:
Primary Carbon: Attached to one carbon onlySecondary: Attached to two carbon atomsTertiary: Attached to three carbon atoms.
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3. Aldehydes
• Organic compounds in which a carbonyl group (C=O) is found on the end carbon (a primary carbon):
• Naming: Substitute –AL in place of final –E of alkane name.
• General Formula
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Propanal
4. Ketones
• C=O group is on the inside of a hydrocarbon:
• Naming: Substitute –ONE in place of final –E of alkane name.
• General Formula:
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Propanone
5. Ethers
• Two carbon chains are joined together by an oxygen atom:
• Naming: name the alkyl groups and add ether at the end.
• General Formula: R-O-R
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Methyl ethyl Ether
6. Organic Acids
• Organic compounds that have a Carboxyl group (-COOH):
• Naming: Substitute –OIC ACID in place of final –E in alkane name.
• Ethanoic acid= Acetic acid• General Formula:
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Ethanoic Acid
7. Esters
• General Formula:
• Have strong aromas; for example, flavorings in bananas, wintergreen, oranges.
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The fine smell of esters
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O
O
PINEAPPLE
O
O
BANANA
O
O
ORANGE
O
O
APRICOT
H O
O
ARTIFICIAL RUM FLAVOUR
8. Amines• Formed when one or more of the hydrogen’s in
ammonia is replaced by an alkyl group:
• Naming: Substitute –AMINE in place of final –E of alkane name.
• General Formula:
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9. Amides
• Formed by the combination of 2 amino acids:
• General Formula: • Form proteins• Naming: Replace final –E with -AMIDE
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Aim: How do organic compounds react?
Do Now: Name the Functional Group:1. CH3COOH
2. CH3COOCH3
3. CH3CHO
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Organic Reactions
• Occur more slowly than inorganic reactions because of the covalent bonds.
• There are 7 types of Organic Reactions.
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Substitution
• Involves the replacement of 1 or more of the hydrogen atoms in a saturated hydrocarbon with another atom or group:
• C2H6 + Cl2 C2H5Cl + HCl
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+
Addition• Involves adding 1 or more atoms at a double or triple bond:
• Ethene + Chlorine 1,2 dichloroethane
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Fermentation
• A chemical process in which yeast cells secrete the enzyme zymase and break down glucose into carbon dioxide and ethanol:
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Esterification
• Reaction between an organic acid and an alcohol to produce an ester plus water:
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Ethanoic acid + Ethanol Water + Ethyl ethanoate
Saponification
• When an ester reacts with an inorganic base to produce an alcohol and a soap:
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Fat + Base Glycerol + Soap
Combustion• Almost all organic compounds will combust , or
burn:
• Compound + Oxygen Carbon Dioxide + Water
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Polymerization
• Polymers: Organic compounds made up of chains of smaller units (monomers) covalently bonded together.
• Polymerization: Formation of these large polymer molecules.
• Examples of Natural Polymers: Cellulose, Proteins, & Starch
• Synthetic Polymers: Nylon & Rayon
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Condensation Polymerization
• Bonding of monomers by removing water from hydroxyl groups and joining monomers by an ether or ester linkage:
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Summary: Identify the Reaction
1. C2H6 + Cl2 C2H5Cl + HCl
2. C6H12O6 2C2H5OH + 2CO2
3. CH3COOH + CH3OH CH3COOCH3 + H2O
4. nC2H4 (C2H4)n
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Carbon • Carbon forms four bonds always!• Carbon can form single, double, or triple
bonds.• Single = Saturated• Double or Triple = Unsaturated• Carbon can covalently bond to other
carbon atoms.
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Hydrocarbons• Have hydrogen and carbon atoms only!• Homologous Series: Members that have
similar properties.• 3 Types: Alkanes, Alkenes, and Alkynes
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Alkane• All single bonds• All end in –ane• Each member differs by 1 carbon and 2
hydrogen atoms.• General Formula: Cn H2n + 2
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Formulas• Molecular:• Shows the kind and
number of atoms in a compound.
• Example: CH4 or C2H6
• Structural:• In addition, shows the
bonding patterns and two-dimensional view.
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Isomers• Isomers: When a molecular formula can
be represented by more than one structural arrangement
• Isomers have the same molecular formula, but different physical and chemical properties.
• As the # of carbon atoms increases, so does the # of possible isomers
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Functional Groups
• Found on Table R!• Alcohols: Can be classified in two ways:1. Primary, Secondary, or Tertiary (with
ONE -OH group only)!2. 1 –OH: Monohydroxy• 2 -OH: Dihydroxy• 3 –OH: Trihydroxy
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Organic Reactions
7 Types: Need to know reactants & products.CombustionSubstitutionAdditionEsterificationSaponificationFermentationPolymerization: Addition & Condensation
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Organic Reactions
• Occur more slower than inorganic reactions. Why?
• Review: Covalent bonds have low melting and boiling points, are poor conductors, and are nonpolar substances.
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Cis-Trans Isomerism
Does the term “trans” have anything to do withthe topic of “trans-fats” we have been hearing a lot about recently?
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