POLLUTION• POLUTION : is the introduction of the

contaminants chemicals into the earth and the atmosphere in large.as result there is a change to the nature

Hypothesis:1. Are they replacement of CFCs?.

2. can the impact of ultraviolet radiation

• Aim: 1.reduction of air pollution 2. Usage of CO2 due to its non

flammability, non- toxicity, cheap

AIR POLLUTION

Air pollution: is the introduction of the chemical substances into air ,so it cause the change to the air percentage composition.

Example of air pollutants :carbon dioxide ( C02),chlorofluorocarbons(CFCs).

EFFECTS OF CHROLOFLUOROCARBONS :OZONE DEPLETION

• Ozone :is an atmospheric gas found in both troposphere and the stratosphere .

• Ozone comes from greek word meaning to smell.

• It is also oxygen that has changed from normal diatomic molecules (02) to triatomic form (03).

• hv+02 03

• Energy is needed for that reaction for taking places ,this will help us to understand why ozone forms oxygen when is subjected to electrical spark or lightning.

• Ozone has an important role in our dial life because it is in charge for protecting earth’s surface from ultraviolet radiation which may cause cancer.

Chlorofluorocarbons.• Are compounds composed by elements

chlorine, with fluorine ,and carbon.

• Chlorofluorocarbons don’t occur in nature ,they are made artificially ,also .OH and .NO as free radicals my contribute to the ozone depletion ,they are formed from both natural sources and human activities.

• Mostly CFCs used and cause the ozone depletion have the following formulas C Cl2F2 and C Cl3F.

Uses of chlorofluorocarbons and effect

• Cfcs are non- toxic, non- flammable, cheap, widely• available that makes the most to be you in past years as aerosol

propellants ,as refrigerants ,as fire extinguisher ,this inertness is the main cause that make it them to cause the ozone depletion ,because the strong bond ,and remain for long time in the atmosphere for more than 120 years before is destroyed and penetrate to the stratosphere with their structures intact ,

• As it increase ,there is a decrease in oxygen ,ozone concentration with the ultraviolet radition generate energy of photon to break down carbon – chlorine bond

Ozone depletion

• The chlorine resulted as free radical is the one that interact with ozone and break down then ozone layer is destroyed and then we get suffer for high temperature, cause global warming that we will discuss later.

• LET US SEE THE EQUATION TO ILLUSTRATE THE PROCESS:

• Photon +F2C Cl. + .Cl

• Cl. +03 Cl. +02

• Cl0. + 0. Cl. +02

CARBON DIOXIDE

• Global warmg • Global warming is the rise of the temperature

of the atmosphere and oceans.• Is cause by some gases generated from

burning the fuel as carbon dioxide and methane ,nitrogen monoxide.

How is the processs

• The green house gases generated from burning of the fuel ,are accumulated in the atmosphere ,when the sun reaches ,and reflect back to the earth's surface and it caused to be warm and return back and as result it cause the rise in temperature

Its consequences

*rise s of sea level*droughts

*floods*storms

*cause the disrupting to the food production

Remedy to global warming:

.promoting the usage of renewable resources .preventing gas emissions from burning the fuel, and

deforestation.advocating an international climate change agreement.

Question and their respective answers

1.What makes the chroline free radical to break off from the chlorofluorocarbons molecule?

Answer: is the sun’s radiation ultraviolet radition, that is strong enough to causethe homolytic fission of the C-Cl bond.

Q2:What is a chemical catalyst? What makes chlorine free radical to be used as catalyst?

Answer: A chemicam catalyst can be defined as the substances that can be provide an alternative route for the reaction to occur at different transitional state.At the end of the reaction catalyst itself does notUndergoes any chemical change during the reaction.

Ozone hole,as effect of cfcs

LET US TOGETHER AVOID THE USAGE OF CFCS.PRESENTED BY EUGENE UWIRINGIYIMANA

SOURCES:WIKIPEDIA, CHEMISTRY IN CONTEXT FIFTH EDITON,GRAM HILL