Ozone Layer Formation
The ozone layer acts as a shield by absorbing most of the sun’s ultraviolet radiation. It is located within the earth’s stratosphere itself. When depleted, more ultraviolet can reach the earth’s surface. This can prove dangerous to human beings, as well as other living things. In recent decades, there has been a rise in industrial activity and use of products that release Chlorofluorocarbons (CFCs). These gases cause the ozone layer to deplete. Hence, ozone depletion has become an issue of global concern.
While this area does not concern the syllabus usually, it is fundamental for Chemistry students to understand the Chemistry behind the ozone layer depletion. These concepts are emphasized in Chemistry tuition because of the links between Chemistry and global issues. It is highly interesting, and students will enjoy these Chemistry lessons.
Oxygen is made of a double covalent bond, that requires significant energy to break. The ultraviolet radiation from the sun causes these bonds to break, forming oxygen atoms. These atoms are not stable, as you may have read in previous articles. Oxygen atoms possess an unpaired electron and are very reactive without pairing. This oxygen atom then reacts with an oxygen molecule to form O3, Ozone.
Ozone Layer Depletion
The weaker bond in ozone requires ultraviolet radiation of less energy to break up, and so results in the formation of an oxygen atom and oxygen molecule, The oxygen radical could also further react with other ozone molecules to form two oxygen molecules.
Usually, the rate of production would equal the rate of destruction. In Chemistry tuition, our Chemistry tutors will make use of simple equations that enable effective understanding of this overall process. However, there has been an increase in use of man-made pollutants such as CFCs and oxides of nitrogen. This causes increased ozone depletion, resulting in what some scientists call ‘large holes. These holes are highly dangerous, and the ultraviolet radiation can directly reach the earth’s surface and can result in conditions such as skin cancer.
The high energy from the ultraviolet radiation causes homolytic fission. This process entails the breaking apart of the Carbon-Chlorine bond in CFCs, as it is the weaker bond. Our Chemistry tutors will draw on earlier concepts of bonding in Chemistry tuition to explain how chlorine atoms will be highly reactive. These radicals cause ozone to break down, resulting in more radicals formed. This keeps occurring until the radicals escape or terminates. Given its ability to reuse itself in a reaction, CFCs are highly undesirable and so there have been increasing regulations worldwide to limit its use. The reaction occurs similarly in the case with oxides of nitrogen, that has equally undesirable effects.
Evidence of Ozone Depletion
Our Chemistry tutors will draw upon evidence in Chemistry tuition lessons to facilitate the reasonings for such occurrences. These theories were justified when some scientists monitored the increasing levels of chlorine monoxide over the Antarctic region. It accordingly reflected the decrease in concentrations of ozone.
Using Chemistry to find better alternatives to CFCs/NOx
Scientists are considering replacing the use of the current pollutants with hydrofluorocarbons (HCFCs) instead. While these also result in the depletion of the ozone layer, it is to a much smaller extent. Our Chemistry tutors will take time during Chemistry tuition lessons to discuss alternative solutions that they could apply from other topics, which makes the sessions highly engaging and enjoyable.
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Chemistry Tuition Singapore @ MY CHEM CAFE
Principal Chemistry Tutor: Mr. Jacky Wong