Alkanes (4c)

Alkanes

• saturated hydrocarbons: only singe C-C bonds, no double

• general formula is C_nH_2n+2

• unreactive generally

• can undergo combustion, can be cracked into smaller molecules, can react with halogens in the presence of light

• ex: Methane

Methane

CH₄

Ethane

C₂H₆

Propane

C₃H₈

Butane

C₄H₁₀

Pentane

C₅H₁₂

Alkanes’ Substitution Reaction

• one atom is swapped with another

• alkanes undergo substitution in the presence of UV radiation

Methane and Bromine reaction in UV Radiation

• methane + bromine → bromomethane + hydrogen bromide

• CH₄ + Br₂ → CH₃Br + HBr
  

also reacts with Chlorine the same way

• methane + chlorine → chloromethane + hydrogen chloride

• CH₄ + Cl₂ → CH₃Cl + HCl
  

Halogenalkanes

• formed from halogen + alkane reactions in UV radiation

• also called haloalkanes

• used as solvents, refrigerants, propellants and pharmaceuticals

CFC

• chlorofluorocarbon

• important haloalkane

• slowly phased out due to ozone damage

• previously used in fridges and ACs