Galvanic Cell (3 Viewers)

[mirror-match]

God im so noob, from previous question i put that salt brindge should be KOH . EPIC FAIL.

 

[Michaelmoo]

Yeah i know, i just asked her if i was right when i put down KNO3

Looks like i got this question all right. Yatta!

Good job!

 

[chrisnumber1]

damn sounds like i got this almost completely wrong...
i had a good look at my sheet at the back
saw lead was in the middle of Fe3+ and Fe2+
this is what i did
the potential difference between Pb and Fe3+ was some answer
then because Fe2+ was on top of Pb i found the potential difference here and minused it from my first one... because it was going in the opposite direction therefore opposing.
another thing i was thinking of doing was saying the Fe3+/Pb was greater than the other so i was only gonna use that but instead decided the test was easy up till here and mabe... owell i got anode and cathode

wooo 1000 posts =)

that sucks, yeah i was confused then saw it on the sheet, unlucky

 

[lynton]

wow- i completely disregarded the fe3+

i saw that fe2+ was on top and therefore it oxidised whilst the pb was in the middle and therefore it was reduced. Hope to get some marks. Any would be good that this moment in time. Majorly freaking.

 

[Melisoverschool]

damn i got it all right except i labelled the anode and cathode on the wrong side... how many marks out of three would i lose?

 

[megaman]

I must admit I felt pretty good about that paper and should get above 70% raw. By the sounds of it I fumbled my way through the galvanic question and got most of it right at least which makes me happy =).

 

[Randomist]

I think I got full marks for this question - so pleased

 

[Gibbatron]

I think i went ok in this question. Ive got pretty much what everyone else got - i made sure i learnt galvanic cells cause id completely forgotten how to do them.

 

[postcardsfrom]

Thanks for this post, feeling quite good about this. What was with the last question in forensics?? I think the answers are going to be so varied with that one.

 

[carlytse621]

God im so noob, from previous question i put that salt brindge should be KOH . EPIC FAIL.

FML. i put KOH too....

 

[random-1005]

I did that, which led me to use Fe > Fe2+ + 2e-
It's further up than lead, so it's oxidised. .:. At Anode (pt). It's reversed, so the potential becomes 0.44V

Then, that leaves Pb to be reduced. So Pb2+ + 2e- > Pb
Thats reduced, so it occurs at the cathode (lead). Potential is -0.13V

.:. 0.44 + -0.13 = 0.31V

Everyone seems to be saying the opposite, but this seems logical. The Fe3+ were spectator ions in solution, not being involved.

If this is wrong, then sorry for leading you all astray.

lol

this is what i did, i hope its correct, mix of fe2+ and fe3+ was dodgy

 

[Gibbatron]

FML. i put KOH too....

FML. Dammit i put it as well. Good thing its only one mark.

 

[Aerath]

lol

this is what i did, i hope its correct, mix of fe2+ and fe3+ was dodgy

But it's like...not correct.

 

[4theHSC]

But it's like...not correct.

I did the Fe(s)>> Fe2+ +2e,, and the Pb oxidised, now I may be wrong on this part,, but peoples do I lose my other marks since its based on the first answer? like the cathode and anode were different, but would it be marked as right based on my first error? just a bit worried about this question

 

[ankgu]

oh shit i put KOH as well...dammit easiest q in the entire paper and thats the one i stuff up

 

[Gibbatron]

I did the Fe(s)>> Fe2+ +2e,, and the Pb oxidised, now I may be wrong on this part,, but peoples do I lose my other marks since its based on the first answer? like the cathode and anode were different, but would it be marked as right based on my first error? just a bit worried about this question

You don't lose marks if you based a second part of a question on the first part. You'll lose marks in the first part but shouldn't in the second if your method is correct.