Organohalogen compounds in the environment

Question 1

organohalogen compounds are molecules that contain at least

Answer 1

one halogen atom joined to a carbon chain

Question 2

uses of organohalogens
()
_
_
_
_
_

Answer 2

(in pesticides)

• general solvents
• dry cleaning
• making polymers
• flame retardants
• refrigerants

Question 3

ozone layer is found _______ at a height of abt ________ above earths surface.

Answer 3

outer edge of stratosphere, 10 to 40km,

Question 4

only a tiny fraction of the gases making up the ozone layer is ozone but is enough to absorb most of biologically damaging ultraviolet radiation from suns rays linked to sunburn, skin cancer, genetic damage. it is feared that continued depletion of ozone layer»allow more UVB radiation to reach earth surface»bad for organisms bc….

Answer 4

just remember it

Question 5

in the ______, ozone is continually being ______________ by the _____ of __ radiation. initially _ ____ energy breaks oxygen molecules into oxygen _______ : (equation)

a _____ state is then set up involving O2 and the oxygen radicals in which ____ forms and then breaks down. rate of formation of ozone in this steady state is the _____ as the rate at which it is _____ _____: (equation)

PRODUCTION AND USE OF ____ HAS UPSET THIS DELICATE ___________

Answer 5

stratosphere, formed and broken, action, UV, v high, radicals, O2–> 2O

steady, ozone, same, broken down,
O2+O O3

CFCs, EQUILIBRIUM

Question 6

until recently CFCs and ____ were most common compounds used as refrigerants, in _________ units, and as aerosol _________.
CFCs are v ______ bc of the _______ of the _____-____ bonds within their ________

Answer 6

HCFCs, air-conditioning, propellants, stable, strength, carbon-halogen, molecules

Question 7

In 19__ two chemists, Frank S. _____ and Mario _____ concluded that CFCs remain _____ until they reach the ________.
Here the CFCs begin to ____ ____ forming ______ _____, tht are thought to ______ the _______ of the ozone layer.
In 19__, Rowland and Molina were awarded Nobel prize for discovering this ozone depletion

Answer 7

73, Rowland, Molina, stable, stratosphere, break down, chlorine radicals, catalyse, breakdown, 95,

Question 8

How do CFCs deplete the ozone layer?
the stability of CFCs, due to the strength of their carbon-______ bonds means that CFCs have a ____ ________ ____ in the ____sphere. it may take them ______ to reach the ____sphere.

once in the stratosphere __ radiation provides sufficient energy to break a carbon-halogen bond in CFCs by ________ _____ to form ______. the __-__ bond has the _____ bond enthalpy and so is the bond that breaks.

Answer 8

halogen, long residence time, troposphere, stratosphere

uv, homolytic fission, radicals, Cl-Cl, lowest

Question 9

as radiation initiates the breakdown this process is called

Answer 9

photodissociation