HSC 2012-2015 Chemistry Marathon (archive) (2 Viewers)

[deswa1]

re: HSC Chemistry Marathon Archive

- Oxidation/corrosion on the surface of the electrodes--> decreasing the EMF
- Incorrectly calibrated laboratory equipment (voltmeter in this case)--> above/below theoretical values.

- differences in surfaces area of the two electrodes
- differences in concentration of the solution in the respective half cells.

Yeah these are valid answers I guess. I was looking for something different (along the lines of Immortalp00n's last point) so I'll change the question a bit:

- Under what conditions was the table of standard potentials developed?

 

[Immortalp00n]

re: HSC Chemistry Marathon Archive

Yeah these are valid answers I guess. I was looking for something different (along the lines of Immortalp00n's last point) so I'll change the question a bit:

- Under what conditions was the table of standard potentials developed?

not to sound like a dick or anything, but isnt the voltmeter point a bit invalid?
like isn't it assumed that we're not using faulty equipment etc...

 

[deswa1]

re: HSC Chemistry Marathon Archive

not to sound like a dick or anything, but isnt the voltmeter point a bit invalid?
like isn't it assumed that we're not using faulty equipment etc...

Yes true. And her other point as well about corrosion on the lab equipment -> sorry Egg...

 

[Immortalp00n]

re: HSC Chemistry Marathon Archive

Yes true. And her other point as well about corrosion on the lab equipment -> sorry Egg...

hm yeh im not like tryna point out mistakes eg haha
just wanna clarify lol...
and des brah, what would u say for the question u put?

 

[Eg155]

re: HSC Chemistry Marathon Archive

Yes true. And her other point as well about corrosion on the lab equipment -> sorry Egg...

My teacher said this as an explicit point (HSC marker) so i unno. (on that point we had to remove any signs of corrosion or oxidation on the metal's surface if it was something reactive like Fe or something... )
... unless u are assuming the metals were not very exposed to the env't at all...

Incorrect calibration can't be considered- why?

 

[Eg155]

re: HSC Chemistry Marathon Archive

Yeah these are valid answers I guess. I was looking for something different (along the lines of Immortalp00n's last point) so I'll change the question a bit:

- Under what conditions was the table of standard potentials developed?

Oh SLC hhhhaha. change temp/atmospheric pressure?Measured against standard hydroden electrode blah blah...

Alter usual:
Concentration 1 Molar
Pressure 1 atmosphere
Temperature 25°C

= change EMF values.

 

[deswa1]

re: HSC Chemistry Marathon Archive

My teacher said this as an explicit point (HSC marker) so i unno.
... unless u are assuming the metals were not very exposed to the env't...

Incorrect calibration can't be considered- why?

Yeah they are correct answers but in my question, I said to assume stuff was pure to stop these sort of responses haha. Obviously in the HSC you could write that, I just wanted to see if people knew the exact conditions standard potentials were created under and thus when these are changed, measured values change.

Oh SLC hhhhaha. change temp/atmospheric pressure?

Yep. And concentration of 1 mol/L as well

 

[Eg155]

re: HSC Chemistry Marathon Archive

Ah I see Was freaking out because I wrote that on my test and we haven't gotten it back soooo *Sigh of relief*

 

[Immortalp00n]

re: HSC Chemistry Marathon Archive

wait wait hold on
so slc temps, pressure can be written in hsc?

 

[Immortalp00n]

re: HSC Chemistry Marathon Archive

Yeah they are correct answers but in my question, I said to assume stuff was pure to stop these sort of responses haha. Obviously in the HSC you could write that, I just wanted to see if people knew the exact conditions standard potentials were created under and thus when these are changed, measured values change.

what r they brah?

 

[deswa1]

re: HSC Chemistry Marathon Archive

Ah I see Was freaking out because I wrote that on my test and we haven't gotten it back soooo *Sigh of relief*

Yeah lol- soz about that. I'm impressed you got the SLC conditions in the end though

 

[Eg155]

re: HSC Chemistry Marathon Archive

what r they brah?

See my post man, I got it right! Deswa said okay.

Oh SLC hhhhaha. change temp/atmospheric pressure?Measured against standard hydrogen electrode blah blah...

Alter usual:
Concentration 1 Molar
Pressure 1 atmosphere
Temperature 25°C

= change EMF values.

 

[Eg155]

re: HSC Chemistry Marathon Archive

Yeah lol- soz about that. I'm impressed you got the SLC conditions in the end though

A1.

 

[deswa1]

re: HSC Chemistry Marathon Archive

wait wait hold on
so slc temps, pressure can be written in hsc?

Yeah though the other ones are probs easier. SLC conditions- 25 degrees C, 100kPa and also 1 molar solutions. See HSC 2006 Q19

 

[Immortalp00n]

re: HSC Chemistry Marathon Archive

See my post man, I got it right! Deswa said okay.

Oh SLC hhhhaha. change temp/atmospheric pressure?Measured against standard hydroden electrode blah blah...

Alter usual:
Concentration 1 Molar
Pressure 1 atmosphere
Temperature 25°C

= change EMF values.

tbh i always thought that SLC were an assumption like in order for it to be yield a fair result?
and hence couldnt be used as a valid answer :/ idno brah

 

[Immortalp00n]

re: HSC Chemistry Marathon Archive

from the hsc answers: " He could ensure that the electrolyte solutions are both 1.0 mol L
-1
concentration and the
entire setup is at 25
o
C, as these are the conditions under which the standard potentials
are taken. Additionally, ensuring that the pH of each electrolyte is 7 would minimise the
variation, as acidic conditions would alter the values taken. "

soz eg :3

 

[Eg155]

re: HSC Chemistry Marathon Archive

from the hsc answers: " He could ensure that the electrolyte solutions are both 1.0 mol L
-1
concentration and the
entire setup is at 25
o
C, as these are the conditions under which the standard potentials
are taken. Additionally, ensuring that the pH of each electrolyte is 7 would minimise the
variation, as acidic conditions would alter the values taken. "

soz eg :3

I'm sorry, are you blind? Read what I wrote again m8.

"Alter usual:
Concentration 1 Molar
Pressure 1 atmosphere
Temperature 25°C

= change EMF values."

Therefore, if you cannot deduce from what I wrote: ALTER the conditions under which the standard potentials are taken then then the EMF values are altered.
THEREFORE: to minimise error the experiment should be carried out under SLC conditions which the standard potentials are taken.

Stop.trying.to.make.me.look.stupid.
You took HSC answers which are the same thing as what was already said.

 

[Immortalp00n]

re: HSC Chemistry Marathon Archive

I'm sorry, are you blind? Read what I wrote again m8.

"Alter usual:
Concentration 1 Molar
Pressure 1 atmosphere
Temperature 25°C

= change EMF values."

Therefore, if you cannot deduce from what I wrote: ALTER the conditions under which the standard potentials are taken then then the EMF values are altered.
THEREFORE: to minimise error the experiment should be carried out under SLC conditions which the standard potentials are taken.

Stop.trying.to.make.me.look.stupid.
You took HSC answers which are the same thing as what was already said.

wait what?
im apologising for contesting ur previous answers coz i read hsc answers and it had it?
fucks up urs?

 

[Immortalp00n]

re: HSC Chemistry Marathon Archive

I'm sorry, are you blind? Read what I wrote again m8.

"Alter usual:
Concentration 1 Molar
Pressure 1 atmosphere
Temperature 25°C

= change EMF values."

Therefore, if you cannot deduce from what I wrote: ALTER the conditions under which the standard potentials are taken then then the EMF values are altered.
THEREFORE: to minimise error the experiment should be carried out under SLC conditions which the standard potentials are taken.

Stop.trying.to.make.me.look.stupid.
You took HSC answers which are the same thing as what was already said.

+1

 

[Eg155]

re: HSC Chemistry Marathon Archive

I'm actually really sorry! I misinterpreted

Being so used to you hating on me I assumed it was negative/ you trying to tick me off.

Please accept the PDF through PM as an apology.
*need your e-mail...