Organic Compounds

Definition and Basics

Organic compounds are substances made up mostly of carbon and hydrogen atoms; they may also contain elements like oxygen, sulphur, nitrogen, phosphorus, and halogens.
The key feature of organic compounds is the carbon skeleton, which can be chains, branches, or rings of carbon atoms.
Organic compounds are categorised into different classes: alkanes, alkenes, alkynes, alcohols, ethers, esters, aldehydes, ketones, carboxylic acids, amides, amines, and aromatic compounds.

Alkanes

Alkanes are organic compounds that consist entirely of single-bonded carbon and hydrogen atoms and lack functional groups. Each carbon atom forms 4 bonds (either C-H or C-C bonds).
They are saturated hydrocarbons, meaning they contain as many hydrogen atoms as possible.
Alkanes are generally unreactive except reaction with oxygen - combustion.

Alkenes and Alkynes

Alkenes are hydrocarbons that contain a carbon-carbon double bond. Alkynes, on the other hand, possess a carbon-carbon triple bond.
Both alkenes and alkynes are categorised as unsaturated hydrocarbons since they have fewer hydrogen atoms than alkanes.
Alkenes and alkynes react through addition reactions where the double or triple bond opens to allow the attachment of other atoms.

Functional Groups

The functional group of an organic compound is an atom, or a group of atoms, that has certain chemical properties regardless of the rest of the molecule.
The functional group is the center of reactivity in an organic compound.
Examples include hydroxyl (-OH) in alcohols, carbonyl (>C=O) in aldehydes and ketones, carboxyl (-COOH) in carboxylic acids, and amino (-NH2) in amines.

Isomerism

Isomers are compounds with the same molecular formula but different molecular structures or different spatial arrangements of atoms.
Structural isomers have different covalent arrangements of their atoms.
Geometric isomers, a type of stereoisomer, have the same bond connections but different spatial arrangements due to the inflexibility of double bonds.

Reactions of Organic Compounds

Common types of reactions include substitution, addition, and elimination reactions.
Substitution reactions involve replacing one or more atoms in the compound, often by a more reactive atom or group.
In addition reactions, atoms are added to a molecule without any other atoms being removed.
Elimination reactions involve the removal of atoms from a molecule, often resulting in the formation of a double or triple bond.

Spectroscopy

Spectroscopy (mainly IR and NMR) is a crucial tool in determining the structure and functionality of organic compounds.
IR spectroscopy provides information about the presence of functional groups in a molecule.
NMR spectroscopy provides information regarding the carbon-hydrogen framework of an organic compound.