Hydrocarbons are compounds made from carbon and hydrogen atoms joined by covalent bonds. Alkanes are saturated - they have only single bonds. Alkenes have a double bond - they are unsaturated. Alkenes react with brown bromine water and decolourise it, but alkanes do not.
Alkenes can act as monomers. Under high pressure and in the presence of a catalyst many monomer molecules join together to make polymer molecules. These polymer molecules are saturated.
A covalent bond is a shared pair of electrons.
Alkanes are saturated hydrocarbons. This means their carbon atoms are joined…