types of organic reactions tom nowak cedar house school g12 organic chemistry
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Types of Organic Reactions
Tom Nowak
Cedar House School
G12 Organic Chemistry
Organic Chemistry ReactionsBOLD ONLY = examinable
Addition Substitution Combustion Elimination Esterification Fermentation Polymerization (Addition & Dehydration) Saponification
Addition
Addition reactions occur when atoms are added to an unsaturated molecule (an alkene or alkyne)
+H H
H H
Organic Chemistry Reactions
Addition
1) Define saturated and unsaturated, offer structural formula example of each
2) Explain why unsaturated must be the reactant
Substitution
Substitution reactions occur when one type of atom replaces a hydrogen atom in a saturated (yet not necessary) molecule
+
+H
Cl
ClH-Cl
Organic Chemistry Reactions
Substitution
Give your own example of substitution.
Combustion
Combustion refers to the reaction of a compound with oxygen to produce energy (an exothermic reaction).
There are two types:
Complete combustion - in which CO2 is produced.
Incomplete combustion - in which CO is produced.
Water is also produced in combustion reactions
Combustion is EXOTHERMIC turning chemical potential energy into heat energy
Example of complete combustion:
CH4 + 2 O2 CO2 + 2 H2O
Example of incomplete combustion:
2 CH4 + 3 O2 2 CO + 4 H2O
In addition to the differences in the products, what other difference can you detect between complete and incomplete combustion?
The difference in the two types of combustion involves the ratio of oxygen to fuel:
Complete Combustion:
CH4 + 2 O2 CO2 + 2 H2O
The coefficients tell us that we need 2 oxygen molecules for every 1 methane molecule for complete combustion.
Incomplete combustion:
2 CH4 + 3 O2 2 CO + 4 H2O
In incomplete combustion the ratio is 3 oxygens for every 2 methane molecules
Combustion final
• Explain why fossil fuels contain lots of Chemical potential energy• Explain how fossil fuels release this potential energy With Combustion as thermal heat energy• Explain how fossil fuel engine utilize this heat energy to Do work• Explain how a larger volume engine (liters) is usually More ”powerful”
Elimination
An elimination reaction occurs when 2 substituents or functional groups are REMOVED from a molecule.Elimination can be seen as the reverse of additionLG = leaving group, general term for substituent that is Usually Electron donating/negative (anion) or neutral For example = halides, oxides, other hydrocarbons
H-C-C-LG C=C + H-LG
Organic Chemistry Reactions
Elimination
Describe elimination of alcohol
Describe elimination of alkyl halide
Elimination:Dehydration of alcohol
Elimination: Dehydrohalogenation
CH2Cl – CH2Cl CH2=CHCl + HCl
Elimination: Cracking of hydrocarbons (thermal) =forms radicals &random products
Elimination: Cracking of hydrocarbons (catalytic)= more reliable carbon products
Esterification
+
+
Acid Alcohol
Ester Water
Organic Chemistry Reactions
Esterification
Write an equation to prepare an ester
Identify the reactants from this product
FermentationIn the fermentation reaction a sugar is broken down into ethanol and carbon dioxide
2 + 2
Glucose Ethanol Carbon dioxide
Xymase
Xymase is an enzyme (a biological catalyst)
Polymerization is the process by which a numberof small molecules (monomers) are hooked together to form a larger molecule (polymer). This is like forminga train from a bunch of individual railroad cars.
Monomers
Polymer
Addition Polymerization
In this type of polymerization, the links between the monomers are formed by the breaking of double bonds.
n
Ethene Polyethylene
Addition polymerization always involves unsaturated compounds
Condensation Polymerization
In this type of polymerization, two molecules react together to form a larger molecule plus some other product (sometimes water).
n
monomer Polymer
In this case, the polymer is held together by ether linkages.
+ H2O
Organic Chemistry Reactions
Esterification Addition Substitution Fermentation Polymerization (Addition & Dehydration) Saponification
Saponification
In saponification, a fat reacts with a strong base to form glycerol and three soap molecules (long non-polar molecules with a polar end)
+ +
FatStrong base
Glycerol Soap
R - represents a long chain of C and H atoms
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