Organic Chemistry (topic 10/20) Flashcards
Homologous series
A series of compounds of the same family, with the same general formula, which differ from each other by a common structural unit.
Structural isomers
Compounds with the same molecular formula but different arrangements of atoms.
Functional groups
Single or groups of atoms that dictate the properties of a group of organic compounds. The reactive parts of molecules.
Saturated compounds
Contain single bonds only
Unsaturated compounds
Contain double or triple bonds.
Alkanes
Alkanes have low reactivity and undergo free-radical substitution reactions.
- Function group: alkyl
- Saturated compound
- General formula: CnH2n+2
Naming Alkanes
- [stem] + ane
ex. propane, butane, methane, etc.
Alkenes
Alkenes are more reactive than alkanes and undergo addition reactions. Bromine water can be used to distinguish between alkenes and alkanes.
- Functional group: alkenyl (double carbon bond)
- Known as unsaturated compound
- General formula: CnH2n
Naming Alkenes
- [stem] + ene
ex. hexene, butene, etc.
Alcohols
Alcohols undergo nucleophilic substitution reactions with acids (also called esterification or condensation) and some undergo oxidation reactions.
- Functional group: OH (hydroxyl group)
- General formula: CnH2n+1OH
Naming Alcohols
- [stem] + nol
ex. propanol, decanol, etc.
Halogenoalkanes
Halogenoalkanes are more reactive than alkanes. They can undergo (nucleophilic) substitution reactions. A nucleophile is an electron-rich species containing a lone pair that it donates to an electron-deficient carbon.
- Formed when a halogen is bonded to an alkyl group
- Functional group: R - X (R being the alkyl group and X being any halogen)
- General formula: CnH2n+1X
Naming Halogenalkanes
- Chloro- /bromo- /iodo- + [alkane]
ex. Bromoethane, iodobutane, etc.
Polymers
Addition polymers consist of a wide range of monomers and form the basis of the plastics industry.
Benzene
Benzene does not readily undergo addition reactions but does undergo electrophilic substitution reactions. Is an aromatic, unsaturated hydrocarbon.
The different characteristics of a homologous series include:
- Members have a functional group
- Molar mass of consequent members differ by 14 kJ mol-1
- Consequent members differ by CH2 group
- Members show gradual trend in physical properties
- Members have similar chemical properties
Empirical formula
Is the simplest whole-number ratio of atoms in a compound.
Molecular formula
Represents the real number of atoms and each type of atom in a compound.
Full structural formulae
All atoms and bonds between all atoms are shown.
Condensed structural formulae
Assumes certain bonds and therefore all atoms need not be shown. Easier to draw.
Skeletal formulae
Removes all atoms, leaving only a ‘skeleton’ of the molecule.
Stereochemical formulae
Shows the three-dimensional positions of atoms around a carbon.
Alkynes
- Functional group: alkynyl (triple carbon bond)
- Known as saturated compound
- General formula: CnH2n-2
Naming Alkynes
- [stem] + yne
ex. butyne, propyne, etc.
Aldehydes
- Functional group: CHO (aldehyde group)
General formula: CnH2n+1CHO
Naming aldehydes
- [stem] + al
ex. butanal, pentanal.
Ketones
- Functional group: -CO- (ketone)
- General formula: CnH2n+1COCxH2x+1 (where x and n are two positive intergers)
Naming Ketones
- [stem] + anone
ex. ethanone, hexanone, etc.
Carboxylic acids
- Functional group: -COOH (carboxyl)
- General formula: CnH2n+1COOH
Naming Carboxylic acids
- [stem] + oic acid
ex. propanoic acid, butanoic acid, etc.
Ethers
- Functional group: -O- (ether)
- General formula: CnH2n+1OCmH2m+1 (where m and n are two positive integers)
Naming Ethers
- [stem of shorter carbon chain] + oxy + [stem of longer carbon chain] + ane
ex. methoxypropane, ethoxyethane, etc.
Esters
- Functional group: -COO- (ester)
- General formula: CnH2n+1COOCmH2m+1 (where n and m are two positive integers)
Naming Esters
- [stem of alcohol] + yl + [stem of carboxylic acid] + noate
ex. methyl methanoate, ethyl propanoate, etc.
Amines
- Functional group: -NH2
- General formula: CnH2n+1NH2
Naming Amines
- Primary Amines
- Secondary Amines
- Tertiary Amines
Primary Amines
- Contain only one carbon connected to the nitrogen in the compound
- [stem] + amine
ex. propanamine, butanamine, etc.
Secondary Amines
- Contain two carbons connected to the nitrogen in the compound
- N-[stem of shorter carbon chain] + yl + [stem of longer carbon chain] + amine
ex. N-methylbutanamine, N-ethylpropanaimine, etc.