RNH 2 23. A petroleum fraction is a mixture of hydrocarbons which have boiling points in a given range, e.g. the 30 to 200 degrees centigrade fraction. Petroleum fractions are produced at a refinery by fractional distillation. Other important greenhouse gases are chlorofluorocarbons and hydrochlorofluorcarbons. Oxidation of organic chemicals usually involves addition of oxygen or removal of hydrogen.
Reduction usually involves addition of hydrogen or removal of oxygen.
If you look at how the oxidation number of the affected carbon changes you will see that this is true. In high density polyethylene the polymeric chains are straight and unbranched. This allows the chains to lie close together giving a high density material. In low density polyethylene the polymeric chains have branches which keep the chains separated. HOCH 2 CH 2 OH 69.