a common chem question (apparently) (1 Viewer)

[mitochondria]

I was asking about photochemical smogs @ the beginning but then everything turned out to be referring to a common dot point:

assess the evidence which indicates increase in atmospheric concentration of oxides of sulfur and nitrogen

it seems that the evidence we have are not sufficient to indicate the atmospheric concentraion of these substances because:

- we do not have instruments that can measure the concentration of SO2 and NO2 accurately until recently
- unlike CO2, SO2 and NO2 tend to not stay in the atmosphere or as insoluble forms like carbonates formed from H2CO3
- the concentration of CO2 can be compared with the amount of CO2 that is trapped in polar ice
- CO2 do contribute to acid rain to a certain extend
- there is not enough evidence for the comparison of past and present concentration of SO2 and NO2



*sigh* got it all wrong about photochemical smogs and acid rain in the first place... lucky mee have never been asked in exams

 

[Ragerunner]

But is that beyond the scope of the syllabus?

As long as the majority of the textbooks have the answer we write it should be fine.

 

[mitochondria]

oooh.. poor you... but i thought mentioning CO2 was werid and couldn't get over the idea that it is not worth mentioning.. so i just rang them again.. and i asked specificly this time: why do you have to mention CO2 in this dot point..

and the answer is, depending on what the question, but most of them time you don't have to focus on CO2 as the question is asking you about sulfur oxides and nitrogen oxides..

you know.. the information they have on CSU is quite dodgy.. check it out.. it's all about CO2..

and yeah.. that guy who answered my questions did also mention about a 7 mark question in one of the trial papers this year.. poor you.. but still.. there's still the HSC and we all know trial papers suc* (do we?)

oh.. and by the way, i managed to scab a question without having to pay (does anyone think that the one question per call is a bit dodgy? or is it just me? wouldn't a call per time unit be better?).. i asked whether we could use abbreviations without losing mark in the HSC.. and he said it depends on the question, if a question ask you to "describe" rather than "identify" you would probably better off to not use abbreviations at all (e.g. PVC maybe used instead of Polyvinvinvinvinvinly Chlolololololorite.. oops.. see it's long)

and guess what.. does anyone use Conquering Chemistry? they also have lotsa information on CO2 and defocused themselves from sulfur and nitrogen oxides *i think*... why do we want to write CO2 is trapped in polar ice when we are talking about sulfur oxides and nitrogen oxides?

so now instead of saying all those things above, talk about:
- acid rain
- photochemical smog
- that SO2 and NO2 are soluble, thus, the concentrations of them in the atmosphere are reduced
- concentration of SO2 and NO2 were hard to measure until recently instruments with hi accuracy are available
- link it with the formation of acid rain and identify that the frequency of acid rain has increased as SO2 and NO2 contribute most to the pH of acid rain and this could mean the *emission* of SO2 and NO2 are thought to have increased, but link this back to the fact that they are soluble and therefore the concentration of them *in the atmosphere* do not shift significantly
- *still* there is not enough evidence from the past like CO2 (maybe this is where it comes in) to compare the concentration of SO2 and NO2 with what it is today

So maybe after all CO2 doesn't fit in too well

d'love to hear everyone else's idea on this dot point...

Good Luck everyone!

 

[iambored]

i asked about that dot point yesterday, they told me it was the industrial revolution stuff that's in conq

 

[braindrainedAsh]

This is all that I had in my summary:

The burning of coal and petroleum products as well as the smelting of minerals has led to a significant increase in the levels of acidic oxides in the atmosphere. This is particularly true for heavily industrialized nations, such as the USA. The annual average concentration of SO2 and NO2 in most large cities around the world is about 0.01 for each gas. This is about ten times the value for clean air. In Sydney and Melbourne there is some concern about the number of days per year that the safe levels for these gases are exceeded.

I guess this isn't really right, because it isn't really "asessing the evidence"..... damn

 

[sugaryblue]

i never really referred to CO2 in this dot point. I just remember that they need equations to get marks and I lost a lot of marks because I hate memorising equations.

I've made my mistakes but I am not going to make them again!

 

[yasminwright]

Your right, no matter what you have written the examiner loves equasions for an easy extra mark.... don't forget sub-scripts though!

 

[iambored]

oh, i don't have equations in this point...

 

[iambored]

does this dot point also have something to do with acid rain? more oxides in air, more acid rain, more corrosion

 

[loser]

What effect does this have on the price of fish in Mexico?

 

[iambored]

Originally posted by loser
What effect does this have on the price of fish in Mexico?

does what have?