PHYSICAL CHEMISTRY COURSEWORK Example | Topics and Well Written Essays - 1000 words

PHYSICAL CHEMISTRY - Coursework Example Average Lifetime for CH4 is 8.13 years, in this case it’s a first order chemical loss for X(CH4) With Rate Constant KC=3Ãâ€"10-15, The chemical loss is L=Kcm so that Tc is simply the inverse of the rate constant (Naylor, 1995) (a) The most abundant oxidants in the Earths atmosphere are O2(oxygen), O3(ozone) and OH(hydroxyl ) Radical group. These oxidants have large bond energies and are hence relatively unreactive except toward radicals (O2 only toward highly unstable radicals). With a few exceptions, oxidation of non-radical atmospheric species by O2 or O3 is negligibly slow. Of the three, OH radical is identified as a strong oxidant in the stratosphere. OH reacts rapidly with most reduced non-radical species, and is particularly reactive toward H-containing molecules due to H-abstraction reactions converting OH to H2O. Oxygen and Ozone:O2 and O3-oxygen is a principal constituent of dry air, accounting for 21% of the atmospheric volume, atmospheric oxygen is regulated by a slow atmospheric lithosphere cycle involving conversion of O2 to Carbon dioxide. Elements that combine with oxygen remove it from atmosphere; these are described as oxygen sinks, oxygen also combines with other elements to make oxides, the process of chemical change involving oxygen molecules and electrons is both oxidation and reduction, thus its relative activity in the atmosphere (Naylor, 1995) Ozone is generated by the energetic action of solar ultraviolet radiation (UV) on Ordinary Oxygen in the presence of stabilizing agent like Nitrogen. The reaction is reversible and O3 reverts to diatomic oxygen. It’s a strong oxidizing agent readily reacting with other chemical compounds to make toxic oxides, it’s also responsible in providing the strong oxidant OH and its also an important greenhouse gas, however its being depleted at high rate due to emissions due to human