14.4 Alkanes
Each carbon atoms in an alkene has four covalent single bonds – this makes them quite unreactive. They only have two reactions:
–combustion this can either be:
–complete: meaning there is enough oxygen supply so water and carbon dioxide form.
e.g. CH4 + 2O2 → CO2 + 2H2O
OR
–incomplete: meaning there is not enough oxygen to burn them cleanly so either carbon monoxide and water
or carbon and water form.
e.g. 2CH4 + 3O2 → 2CO + 4H2O or CH4 + O2 → C + 2H2O
–chlorine substitution: sunlight is necessary (or any light?). A chlorine atom replaces a hydrogen atom. This can happen to all of the hydrogen atoms if there is enough chlorine.
e.g. CH4 + Cl2 → (light) → HCl + CH3Cl / CH2Cl2 / CHCl3 / CCl4 these compounds are called chloromethane / dichloromethane / trichloromethane / tetrachloromethane