Rucete ✏ Chemistry In a Nutshell
Isomerism arise when two organic compounds have the same molecular formula but different structural formulas.
Structural Isomer
It is occurs as compounds with different structural formula.
 |
| Comparison of Molecular and Structural Formula |
There are three main types of structural Isomers.
Chain and branched-chain isomers
These compounds have different carbon skeletons.
The melting and boiling points of branched chain compounds are smaller than those of straight chain isomers. This is due to the fact that branched chain molecules take up more space when packed together in solid and liquid states, resulted in weaker intermolecular forces.
Positional isomers
These have the same carbon skeleton. However, they have the functional group is attached to different positions on their carbon skeleton.
Since they share the same functional group, positional isomers have identical chemistry; however, the positioning of the function group can lead to variations in physical properties.
Functional group isomers
These occur since isomeric molecules have different physical and chemical properties when they belong to different homologous series.
1. Aldehydes and Ketones
They have same number of C atoms
Their Molecular Formula is C3H6O [General Formula: CnH2nO]
Propanal : CH3CH2CHO
Propanone : CH3COCH3
2. Alcohols and Ethers
They have same number of C atoms
Their molecular formula is C2H6O [General formula: CnH2n+2O)
Ethanol : CH3CH2O0H
Dimethyl ether : CH3OCH3
3. Alkenes and Cyclic Alkanes
Their molecular formula is C4H8 [General formula: CnH2n]
But-1-ene 
Cyclobutene
4. Alkynes and Cyclic Alkenes
Their molecular formula is C3H4 [General formula: CnH2n-2]
Propyne : HC≡CCH3
Cyclopropene
5. Carboxylic Acids and Esters
Their molecular formula is C2H4O2 [General formula: CnH2nO2]
Ethanoic Acid : CH3COOH
methyl methanoate : HCOOCH3
Tags:
Chemistry in a nutshell