Help me!!!! with acidic environment (1 Viewer)

[frodo]

Hey,
can anyone help me with the dot point in the acidic environment syllabus - 2.2.8 - assess the evidence, which indicates increases in atmospheric concentration of oxides of sulfur and nitrogen.

Thanx

 

[Toodulu]

um well
Sulfur dioxide comes from natural sources like volcanoes and smoke from bushfires. and since the industrial revolution, there has been the burning of fossil fuels (coal + petroleum + smelting of sulfide ores) and they contain some compounds of sulfur as impurities which gets given off to the atmosphere.
Nitrogen oxide forms in high temperature combustion environments (in high temp, N and O react) like from electricity generation and car engines.

so basically since the industrial revolution and the developments of the 20th century, the concentration of sulfur dioxide and nitrogen oxide in the atmosphere has increased. And you know that because of the formation of acid rain, which is rain being acidic due to the sultur and nitrogen dioxides being converted to acids that dissolve in the rain. those two also led to the London smogs of the 1950s and just air pollution generally.

 

[Ragerunner]

if you want band six you HAVE to include equations.

main ones are

S + O2 --> SO2 (sulfur dioxide produced usually by ore smelters/volcanoes)

SO2 + H20 --> H2SO3 (The sulfur dioxide combines with water to produce sulfurous acid which is bad to us/environment. respiratory problems/corrosion of limstone/marble buildings)

and for Nitrogen oxides....well i can't be bothered typing that much

 

[mei_ling03]

with this dot point you have to address the validity of the technologies that indicate rises in concentrations of these different atmospheric concentrations.
so you can talk about the accuracy of the technologies from about 1950s and how theres is little evidence showing the levels before that time. only until recently technologies have been developed to measure accurately the ppm. you can also talk about how sulfur and nitrogen are washed out of the atmosphere by acid rain. so these levels would be extremely high in industrialised areas (nearby natural areas are also affected).
that's about all i can think of off the top of my head...

assess = make a judgement based on criteria.

 

[mei_ling03]

just like tudulu said, talking about the formation of acid rain as a result is a good idea. i think for this dot point, chem equations aren't necessary (in the HSC marking from last year they said too many people put in uneccessary equations)...but at the same time it can't hurt...

 

[Toodulu]

if it's a big question worth a few marks then you have to include equations, even if they're really simple. like mei_ling said, it can't hurt.
i'm not quite sure about the accuracy of the technology available thing. i don't think we've spoke about it in class and i can't see how it's directly related to the dot point.

 

[mei_ling03]

yeah i think i just read the message wrong..sorry... must've recalled it from somewhere else. but anyhow, my main message is to know the hsc verbs. if anyone tried answering that in the exam with simply where the oxides come from and their effect or something at level, they wouldn't do very well.
basically the dot point is asking whether the evidence is reliable enough to say there has been an increase in SO2 and NOx. it's one of the high order verbs so it probably would be worth a fair bit if in the exam.
1. identify the evidence, e.g. acid rain
2. state the criteria - how it forms (equations), it's effects (e.g. respiratory probs), any other info (e.g. acid rain gets washed out - is there really an increase in ATMOSPHERIC concentrations - temporary or long term?)
3. conlusion / judgement