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The Atmosphere
Chlorofluorocarbons (CFCs)
CFCs are used are refrigerants, propellants in aerosols, blowing agents for making expanded plastics
and as cleaning solvents. CFCs are good for this because of their low reactivates, low boiling points,
low toxicity and high stability.
However, CFCs are estimated to have a lifetime in the…

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Is human activity responsible?
Human activities are increasing the atmospheric concentrations of `natural' greenhouse gases
e.g. CO2 and gases that are not naturally present e.g. CFCs. Although only present in small
amounts, each CFC molecule has a large `global warming potential' (GWP).
These gases absorb radiation in the `window'…

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The atmosphere is divided into three sections ­ the troposphere, the stratosphere and the
ionosphere. The troposphere, the section closest to the Earth's surface is made up of about 78%
nitrogen and 21% oxygen. The remaining 1% is a mixture of gases, mainly argon, and carbon dioxide.
Human activity alters…

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redistributed when the bond breaks. this can occur in one of two ways:

Heterolytic fission both the electrons of the shared pair go to just one of the atoms when the
bond breaks- this forms ions. H=Cl -> H+ Cl-
In Homolytic fission one of the two electrons in the…

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Dynamic equilibrium
A chemical reaction has a forward reaction, but also a backward reaction. if the backward reaction is
significant then the reaction is reversible. When the rate of the forward reaction is the same as the
backward reaction a system is said to be in dynamic equilibrium.
Steady state…

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At higher pressure and concentrations, particles are in closer proximity to each other
encouraging more frequent collisions
at higher temperatures, a much high proportion of colliding particles have sufficient energy
to react and more particles are able to overcome the activation enthalpy barrier
with smaller particles of reactant there is…


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