Chem Dp Help~ \(^0^")/ <----gay (2 Viewers)

[inasero]

hehe now that i have your attention. I would appreciate if you could tell me what u have written for the following:

1. Compare properties of gaseous forms of oxygen and the oxygen free radical

2. anal-yse the info available that indicates changes in atmospheric ozone conc. describe the changes involved and explain how this info was obtained

3. Plan and perform a first hand investigation to compare the effectiveness of different protections used to coat a metal such as iron and prevent corrosion if you would be so kind as to post up ur experimental results...

4. explain that acidic environments accelrate corrosion in non-passivating environments

5. perform and investigation to compare and describe the rate of corrosion of metals in different acidic and neutral solutions
again resulats would be greatly appreciated

thanks in advance~

 

[Ragerunner]

That's quite a lot to answer.

Try going to the Charles Sturt University site.

 

[inasero]

the reaosn im asking these questions is cos i believe they are convered inadequately by resources and havent done experiments thoroughly in class, so help would be appreciated

 

[Constip8edSkunk]

1. O radical due to an incomplete electron octect is a much stronger oxidant and is extremely reactive

2. ozone depletion due 2 cfcs first predicted in 1974
first observed by UV spectrometer in antarctica by british scientists in mid nineties
this is followed by satellite graphing of earth using total ozone mapping spectometry (TOMS) from 87 onwards by NASA
ozone hole getting bigger through out nineties, peaking in 99
arctic hole started appearing in 95

3. screw results... you end up bullshitting based on what u know neway

4. hydrogen ions oxidises iron: Fe+2H+->Fe2+ +H2
it also removes OH ions form the reduction half eqn of aerated corrosion of iron: O2+H2O+4e- -> 4OH-, shifting eq. to the right

5. again bs based on what u know

 

[toknblackguy]

i'm HOPING that 3,4,5 are from an option?
with the radical, the unpaired lone electron causes extreme reactivity (not sure why) . ozone also has lower MP, BP, stronger oxidiser and is a less stable thing than molecular oxygen

i think with the info was also found through analysis of antarctic ice, where air and stuff was frozen and trapped from like millions of years ago. well..i know this definitley applies to the CO2, but not so much to So2 and NOx...

 

[mon_mon]

The free radical is so reactive because Oxygen really really wants another atom to become a molecule. High electron affinity i think its called. I assume 3,4 and 5 are from Shipwrecks and Salvage?

 

[toknblackguy]

aah...so then monmon, does that mean that the radical is more electronegative...

 

[mon_mon]

Umm...yes. becasue it isn't stable, ie: it's Valence is -2 as opposed to 0. Thus, it is searching for another atom that can stabalise it, for instance another O.

 

[hipsta_jess]

Originally posted by Ragerunner
Try going to the Charles Sturt University site.

the CSU site doesnt have shipwrecks and salvage

 

[mon_mon]

But its still a really good site for chem revision. All ye out there! hear this! CSU is good. And i'm not even getting paid.

 

[+:: $i[Q]u3 ::+]

Originally posted by inasero
hehe now that i have your attention. I would appreciate if you could tell me what u have written for the following:

1. Compare properties of gaseous forms of oxygen and the oxygen free radical

2. anal-yse the info available that indicates changes in atmospheric ozone conc. describe the changes involved and explain how this info was obtained

3. Plan and perform a first hand investigation to compare the effectiveness of different protections used to coat a metal such as iron and prevent corrosion if you would be so kind as to post up ur experimental results...

4. explain that acidic environments accelrate corrosion in non-passivating environments

5. perform and investigation to compare and describe the rate of corrosion of metals in different acidic and neutral solutions
again resulats would be greatly appreciated

thanks in advance~

argh.. i dunno how to separate out the quotes.. =P oh well.

1. A single oxygen atom in its lowest energy state is said to be in its ground state. When UV splits diatomic oxygen, the resulting free radicals have unpaired electrons. These radicals are in a higher energy state than ground state atoms. This energy, along with the unpaired electrons, makes the free radical highly reactive. duatomic Oxygen is moderately reactive, and a moderately strong oxidant, but the free radical, like ozone, is highly reactive.

2. Info can be obtained using UV spectrometers or Total Ozone Mapping spectrometers. (ref conq). the changes observed are that ozone levels have been decreasing significantly since the 1960/1970s, though the rate of decline has slowed in the last decade or so. TOMS also showed that ozone depletion is seasonal, being most intense during early summer./late spring, and that it was localised over the antarctic due to the vortex of cold air.

3. Pop a galvanised nail, a tin can and a painted nail in separate test tubes/beakers. the painted nail will only rust where hte paint is scratched off. The galvanised nail won't rust, as the zinc will rust preferentially to the iron (a white substance forms on nail, ZnO). If coated with tin, rusting will occur at edges of can where tin has been scratched off. Galvanising is therefore the most effective protection; pain will provide a physical barrier only, and iron rusts preferentially to tin.

obviously these are prolli straight from conq/oten so if u have those resources then it'll be useless =P
if u need links, try LMP www.lmpc.edu.au:16080/science
if that doesn't work.. pm me and i'llcheck it.. but it worked for me last time.

ciaoz. ^^

 

[phenol]

board of studies telling everyone lies

oxygen moleucles have unpaired electrons too

arghhhhhh

 

[spice girl]

Originally posted by phenol
board of studies telling everyone lies

oxygen moleucles have unpaired electrons too

arghhhhhh

hahahaha...then why is it stable?

smth to do with bond order?

 

[+:: $i[Q]u3 ::+]

but aren't the electrons on diatomic oxygen paired?

edit: i've jus realised the futility of defying phenol... lol ^^
would u please explain for us then? =) hehe..

 

[spice girl]

according to VSEPR theory, they are paired, but according to another theory (molecular orbital), they're not. experimental evidence suggest the molecular orbital has the last say on this, since liquid oxygen is attracted to a magnetic field (it's paramangetic) and this is due to its unpaired electrons...

 

[Frigid]

Originally posted by spice girl
according to VSEPR theory, they are paired, but according to another theory (molecular orbital), they're not. experimental evidence suggest the molecular orbital has the last say on this, since liquid oxygen is attracted to a magnetic field (it's paramangetic) and this is due to its unpaired electrons...

it's good to know that we don't accept atomic models on face value

 

[phenol]

yup spice girl pretty much got it all there

paramagnetism is very solid evidence there exists unpaired electrons

 

[phenol]

Originally posted by +:: $i[Q]u3 ::+
edit: i've jus realised the futility of defying phenol... lol ^^

no futility i am often wrong too - maybe you can gimme some insight about (AChO phys) maxwell-ampere law in your spare time after hsc - this concept is so much harder to grasp compared to Gauss's law.

 

[+:: $i[Q]u3 ::+]

i could've sworn i'd already replied to this... (??????) *meh.
lol @ acho phys... aust chem olymp phys?? ^^
u'll have no trouble wit it.. maxwell ampere is easier than gauss ^^

 

[mercury]

paramagnetism... haven't heard that for a while.