Ozone layer and Antarctica? (1 Viewer)

[Gosford]

26. Analyse the information available that indicates changes in atmospheric ozone concentrations, describe the changes observed and explain how this information was obtained
Thats the dot point
I've covered most of it
but in my notes i got stuff about antarctica and seasons (how spring = season most depleted)
I guess i should know that but do i need to know equations for winter and spring
eg.
Winter- ClNO2 + HCL --> HNO3 + Cl2
Spring- Cl2 --> 2Cl'
also do i need to know things about the cloud that froms over ANtarctica during winter???
also do i need to know anything else to do with Antarctica with the dot point?
thanx ofr people's help!

 

[wrxsti]

lolz quite a bit of questions.... firstly... you dont need to know the reactions over Antarctica and the cloud and blah blah......

For this dot point this is what i got (which is all you need )

How Informatiom Obtained:
Meterological stations use balloons aircrafts and ground level spectrometers to monitor stratospheric Ozone, satelittes are also used, NASA has a TOMS a total ozone mapping spectrophotometer which covers the entire area of the earth everyday and maps Ozone.

Changes which have been observed:
a 50% reduction of ozone levels was noted between 1975-85 over antartca this was discovered using satelittes, a 40% thinning in the arctic Ozone layer was also observed.. Many areas reported thinning which was worse in summer and spring due to increased UV radiation.

Analysing Information:
Although there seems to be no doubt that Ozone levels are decreasing. Early measurements provided limited information about Ozone. so we do not know accuratlery whether this decrease in Ozone is part of a regular cyclic pattern.

Hope it helps you

 

[Gosford]

thanx
sorry just it seems my teacher has gone overboard for no good reason (except makin me waste time on sutff i dont need to know!)
btw, do we need to know two examples of CFC's + uses (my teacher sed we do!)
thanx again

 

[wrxsti]

thanx
sorry just it seems my teacher has gone overboard for no good reason (except makin me waste time on sutff i dont need to know!)
btw, do we need to know two examples of CFC's + uses (my teacher sed we do!)
thanx again

Nope......
we need to know what CFC's are used for.... (this is what ive got)

CFC's began to be used as propellants, coolants, solvents... due to the fact that they have a low melting point and are very stable.

That is all we need to know

We also need to know 3 equations about CFC's they are (NOTE THESE ARE SPECIFICALLY ASKED)

CCl3F +UV light -> CCl2F + Cl

Clhroine free radicla then destroy ozone

Cl + O3 -> ClO + O2

The chlorine free radical is continually replenished to destroy more ozone

ClO + O -> Cl + O2

Your teacher may be talking about HCFC'a and HFC's
we also DO NOT need to know specific examples and uses of these...
we need to know what they are
If you need any more help feel free to add me
chingy_leb@hotmail.com

 

[jlnWind]

Hey i agree wrxsti
but
i think it is wise that you do know examples but not "needed".
When markers examine 6-8 marks questions, often they will mark
not only on the criteria but the clarity or what you depict as your depth of understanding, examples will add to this apparent "depth of understanding"

Plus, multiple choice always pull out bogus questions soo... yeh

 

[Gosford]

does any1 else wanna get rid of multiple choice
i will post the mutliple choice like every1 got wrong in trioal (unique trial) soon!

 

[jlnWind]

Nooooo multiple choice is fun!
as if youd want to get rid of 20 marks, or is it 15.... -.- worth of questions
which "just by chance" you could get 5, just think what a little study could get you!