Organic Chemistry Chp 11-14 Flashcards
Saturated hydrocarbons:
Only have single bonds
Unsaturated hydrocarbons:
Contain one or more carbon-carbon multiple bonds.
Test for unsaturated hydrocarbons?
Mix with bromine water. If colour change orange- clear is observed, unsaturated hydrocarbon present.
Homologous Series:
A family of compounds with similar chemical properties, where each successive member differs by a alkyl group.
Alkanes:
All c-c bonds are single c-c bonds
Bond Angle of 109.5°
High boiling point, lower than corresponding alcohol
Functional Group:
A part of an organic molecule that effects its properties.
What can carbon covalently bond with?
Hydrogen, oxygen, nitrogen and halogens.
What are the 3 classifications of hydrocarbons
Aliphatic
Aromatic
Alicyclic
Aliphatic:
Carbon atom chain, can be branched or unbranched with non-aromatic rings.
Acyclic:
Carbon atoms joined together in a branched or unbranched ring.
Aromatic:
Some or all of the carbon atoms in a benzene ring (C6H6)
What are the 3 different homologous series?
Alkenes
Alkanes
Alkynes
Alkenes:
One or more c=c double bonds
120° bond angle
Double bond formed by overlapping of p-orbitals
Alkynes:
One or more triple carbon to carbon bonds.
Aldehyde:
CHO - group
-al. - suffix
Ketone.
- C(CO)C- group
- one suffix
Carbonic acid
- COOH - group
- oic acid - suffix
Ester.
- COOC- group
- oate - suffix
Acyl Chloride-
- COCl - group
- oyl chloride - syffix
Amine
- NH2 group
- amine suffix
Nitrate
CN - group
-Nitrile suffix
Alcohol (group, suffix and prefix)
-OH- Group
-ol - suffix
Hydroxy- prefix
Structural isomers:
Same molecular formula, different structural formula.
Stereoisomers:
Same structural formula with a different arrangement of atoms.
Homolytic fission:
Each species takes an electron from the covalent bond, forming two radicals.
Heterolytic fission:
One of the bonded atoms takes both electrons from the covalent bond, forming ions.
Addition reactions:
2 reactants form one product.
Elimination reactions:
1 reactant into 2 products.
Substitution reactions:
Atom or group on molecule is replaced.
How does chain length effect melting point?
Increasing the chain length, increases the surface area, which increases surface contact and-so increases the strength of London forces, increasing the melting point.
How does branching effect melting point?
Branching interrupts contact between chains, reducing the strength of London forces, decreasing the melting point.
Why are alkanes unreactive?
Sigma bond strength.
No polar bonds.
Difficult to react with.
Nucleophiles
Donate electrons to form a chemical bond.
Electrophiles:
Accept electrons to form a chemical bond.
Diff. between E/Z isomerism and optical isomerism
E/Z occurs because of c=c double bonds
Optical isomerism occurs in a range of compounds.
Why does the C=C help cause stereoisomers?
It restricts rotation and-so the groups have fixed positions relative to eachother, meaning that variations are caused by the other carbon being a different orientation.
Cis-Trans isomerism:
Must have at least one of the same groups attached to both.
Alcohol physical properties:
Less volatile, higher water soluibility, higher melting points
Why do alcohols have higher boiling points than their corresponding alkanes?
Although alcohols have smaller London forces, they experience stronger hydrogen bonding because of their polar O-H bond.
Why does the difference in boiling point decrease between alcohols and alkanes as chain length increases?
The London forces of the alkane increase more than the effect of the hydrogen bonding.
What reactions can alkenes undergo:
Hydrogenation, halogenation, hydration, hydrogen halides
Reactions with Alkanes:
Combustion, radical substitution.
Reactions with alcohols:
Combustion, oxidisation, dehydration, substitution of a hydrogen halide.
Alkene hydration:
Alkene + steam with phosphoric acid catalyst (H3PO4)
Alkene hydrogenation
Alkene + hydrogen + nickel catalyst
Halogenation of alkenes
Alkene + halogen at room temp
Hydrogen halide addition and alkene
Liquid alkene + gas hydrogen halide Or Solid alkene + aq hydrogen halide Or Both gaseous Produce 2 stereoisomers
Oxidisation of alcohols:
Alcohol + K2Cr2O7 acidified with H2SO4
Dehydration of alcohols:
Alcohol + conc. Acid (H2SO4 or H3PO4) —-> alkene + water
