Galvanic Cell (2 Viewers)

[Svensson]

i got opposite to yours:mad1:. that is where i get confused, if the direction marked on the salt brige would be much easier.

oh well it's done now
what did you say for the saltbridge? KNO3?

 

[mahdi]

I did 0.77V + 0.13V
which should equal 0.9V (which i think is the correct answer)
but i was rushing and accidently said it equals 1.00V
do you think i will still get the mark?

 

[mahdi]

I said 0.77V + 0.13V
which should equal 0.90V (which i think is the right answer)
but i was rushing and accidently said it equals 1.00V
will i still get the mark?

 

[chopstick]

oh well it's done now
what did you say for the saltbridge? KNO3?

en...i just say that the if the direction marked on the salt bridge will be much easier for me to understand

 

[bayan92]

oh well it's done now
what did you say for the saltbridge? KNO3?

Doesn't potasssium react with Fe ions? I did NH4NO3

 

[TechnIx]

which side is the anode left or right, the direction of electron flow on the diagram is only part really gets me confused?

Anode is LEFT
Cathode is RIGHT

Electrons flow from Anode to Cathode, or, negative to positive.

 

[messagebrd]

i got opposite to yours:mad1:. that is where i get confused, if the direction marked on the salt brige would be much easier.

so what was ur EMF?

 

[TechnIx]

why was this question so hard =S

you look at the Emf table thingo, see which one reaction is higher up and thats the one that oxidises, i.e. that reaction is occurring at the anode. Isn't that the basics of galvanic cells?

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.

 

[chopstick]

Doesn't potasssium react with Fe ions? I did NH4NO3

oh no! please tell me it is KNO3

 

[Svensson]

Doesn't potasssium react with Fe ions? I did NH4NO3

I actually have no idea lol but my text book says "potassium nitrate is a good choice because NO3 and K do not form any ppts with other ions" so I just went off that. But maybe they do??

 

[mitchwong650]

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.

Sorry bud, but there was no iron. It was a platinum electrode and a lead electrode in a solution of Fe2+/Fe3+

there was no Fe(s). therefore lead is oxidised, not the imaginary Fe(s)

 

[Aerath]

i think i stuffed this up but i dont think platinum can be an electrode as it is inert... thus i sed fe2+ is anode and Pb is cathode... however due to my study of indus chem it may have been more likey for Fe3+ to undego redox bcoz it has a higher E valu... in that case it may have been Pb anode and Fe3+ cathode...anybody agree?

How can an ion be an electrode?

 

[mitchwong650]

How can an ion be an electrode?

exactly what i was getting at

 

[annabackwards]

oh no! please tell me it is KNO3

I actually have no idea lol but my text book says "potassium nitrate is a good choice because NO3 and K do not form any ppts with other ions" so I just went off that. But maybe they do??

My teacher said KNO3, so it should be KNO3.

 

[Kakashi Hatake]

so platnium is the cathode, but we use fe(3+) as what is being reduced?

 

[mitchwong650]

My teacher said KNO3, so it should be KNO3.

yes, yes it is =D

so platnium is the cathode, but we use fe(3+) as what is being reduced?

yes.

 

[Michaelmoo]

My teacher said KNO3, so it should be KNO3.

Lol....

KNO3 isn't the only electrolyte you can have. There is more than one answer. It can be any salt solution, as long as it doesn't form a precipitate with any of the reacting ions.

But yes. KNO3 is usually the conventional electrolyte.

 

[TechnIx]

Sorry bud, but there was no iron. It was a platinum electrode and a lead electrode in a solution of Fe2+/Fe3+

there was no Fe(s). therefore lead is oxidised, not the imaginary Fe(s)

Ahh, thankyou! A straightforward explanation
+1 rep

 

[mitchwong650]

Ahh, thankyou! A straightforward explanation
+1 rep

not a problem, thanks

 

[annabackwards]

Lol....

KNO3 isn't the only electrolyte you can have. There is more than one answer. It can be any salt solution, as long as it doesn't form a precipitate with any of the reacting ions.

But yes. KNO3 is usually the conventional electrolyte.

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!