This is a powerpoint presentation describing chloro-fluoro-carbons also known as CFCs

1. By: Brian K Chen

3. Interesting facts

5. Atoms and elements Oxygen -1 oxygen atom is not very important -2 oxygen atoms=the oxygen in the air we breathe -3 oxygen atoms=an ozone molecule Flourine Carbon Chlorine

6. The natural way Normally, the process of producing ozone is very balanced One ozone molecule breaks into two oxygen atoms and one oxygen atom. The two oxygen atoms joins with one oxygen atom form another ozone molecule The one oxygen atom joins with two oxygen atoms to form another ozone molecule. The process is very balanced.

7. What is the ozone layer The ozone layer is part of the stratosphere and is made mostly by one element, oxygen. Ozone itself is a substance. One ozone molecule is made of 3 oxygen molecules. The Ozone layer is part of the stratosphere which is one section of the atmosphere Without the ozone layer, we would be exposed to ultra-violet radiation from the sun. This would cause widespread skin cancer and other problems

8. What is the common perception

10. Where do CFCs come from coolants such as refrigerators and air conditioners. Aerosols like antiseptic sprays

11. The scientific truth Chloroflouro carbons can be written as CF3Cl The C is carbon-1 atom F is Flourine-3 atom Cl is Chlorine-1 atoms After ultraviolet radiation from the sun, one chlorine atom breaks off we have CF3+Cl The single Chlorine atom is the most dangerous.

12. The scientific truth The single chlorine atom will, after it has broken off, combine with ozone molecule and break it into 1 oxygen atom and one oxygen molecule with two atoms. Then it will combine with one of the oxygen atoms.

13. The scientific truth After wards, the combination will combine with an oxygen atom and break down into another oxygen molecule. The following word equations explains this

14. The result The process was balanced but now the CFCs are causing ozone molecules to be destroyed faster than they are being created That is real bad

15. Why is the CFC so dangerous The problem is how long it takes for a CFC molecule to leave the stratosphere Normal physical means cannot get rid of it On average, one CFC molecule can destroy 100,000 Ozone molecules in its life time There are only a few ways of getting rid of it

16. How is the CFC gotten rid of When the chlorine atom collides with other molecules such as hydrocarbons, it forms hydrogen chloride which can leave the atmosphere dissolved in water. Other way is to let the atom slowly drift out

17. What has been done There is the Montreal protocol -It links countries together -In this agreement, they all set aims together to cut producing of CFCs -Singapore is included -It has been changed many times to improve it

18. What should we do????? We should check if the goods we buy such as refrigerators don’t have CFC Do projects like this to raise public awareness

19. Interesting facts In some urban areas although the ozone layer is thinner, there is actually less Ultra-violet radiation reaching the ground This is because of pollution The carbon dioxide and smog in the air actually helps to block the ultra-violet radiation!!!

20. Sources Wikipedia Collins advanced science chemistry http://answers.ask.com/Science/Nature/where_do_cfc_come_from

21. Thanks for watching!!!