production of materials (1 Viewer)

[claybus]

what is a mercury cell?

 

[Paroissien]

Mercury button cell is basically a watch battery. Not used much today because mercury is dangerous

 

[~*HSC 4 life*~]

i think they use silver oxide or something now?

 

[Steven12]

how important is that you know how a battery cell work?

if so, what battery cells should you watch out for?

 

[LSP]

how important is that you know how a battery cell work?

if so, what battery cells should you watch out for?

you should know either dry-cell or lead-acid cell.
AND another one which you can choose from the syllabus options. There are quite a few.
So altogether you just need to know 2 cells. in terms of chemistry, cost and practicality, environmental impact, and impact on society

 

[~*HSC 4 life*~]

mind you, memorising reduction equations for the dry/button cell is a BITCH

 

[Xayma]

How so?

2MnO₂+2NH₄⁺+2e^- ----> Mn₂O₂+NH₃+2H₂O

Ag₂O+H₂O+2e^- ----> 2Ag+2OH^-

Just remember for dry cell Mn goes from oxidation state of IV to II
And for button cell Ag goes from I to 0.

No other atoms have their oxidation state changed it's just a matter of remembering dry cell contains ammonium and water (both of which are in the electrolyte) and button cells contain Water and Hydroxide ions.

 

[mr EaZy]

for dry cells, is the cathode the graphite or is it the manganese
coz the manganese does gt reduced Mg(IV) --> Mg(III)
but the cathode is made up of graphite carbs

 

[Xayma]

But the Carbon is in elemental form. I think it is just to house the manganese and to conduct electricity.

 

[~*HSC 4 life*~]

How so?

2MnO₂+2NH₄⁺+2e^- ----> Mn₂O₂+NH₃+2H₂O

Ag₂O+H₂O+2e^- ----> 2Ag+2OH^-

Just remember for dry cell Mn goes from oxidation state of IV to II
And for button cell Ag goes from I to 0.

No other atoms have their oxidation state changed it's just a matter of remembering dry cell contains ammonium and water (both of which are in the electrolyte) and button cells contain Water and Hydroxide ions.

that helps a bit actually...ta

 

[Paroissien]

How so?

2MnO₂+2NH₄⁺+2e^- ----> Mn₂O₂+NH₃+2H₂O

Ag₂O+H₂O+2e^- ----> 2Ag+2OH^-

Just remember for dry cell Mn goes from oxidation state of IV to II
And for button cell Ag goes from I to 0.

No other atoms have their oxidation state changed it's just a matter of remembering dry cell contains ammonium and water (both of which are in the electrolyte) and button cells contain Water and Hydroxide ions.

The reduction equation I've got for dry cell is:
NH4+ + MnO2 + H2O + e- ---> Mn(OH)3 + NH3

Which is correct?

 

[Tommy_Lamp]

I use the Lithium Ion cell with the Lead/Acid Cell. The Lithium Ion cell half equations arent easy to find but are very simple.

 

[smallcattle]

lol.. i got 2MnO2 + 2H +2e -> Mn2O3 + H2O

which is from excel

 

[Paroissien]

I know everything about my two batteries, I just don't want to write the wrong equation in the exam

 

[Paroissien]

lol.. i got 2MnO2 + 2H +2e -> Mn2O3 + H2O

which is from excel

Excel is garbage. I suggest you go with Xayma's which I plan to do. He seems to know what he is talking about

 

[Tommy_Lamp]

Don't listen to Xayma, he's a fool jk

 

[xeriphic]

anyone have the mercury button cell equation ??

 

[Paroissien]

Anode: Zn + 2OH- ---> ZnO + H2O + 2e-
Cathode: HgO + H2O + 2e- ---> Hg + 2OH-

Straight from Success One so if its wrong it is not my fault

 

[xeriphic]

lol thanks, also was the dry cell equation you put before the full one ??

 

[Paroissien]

Yeah:
Cathode: 2MnO2 + 2NH4+ + 2e- ----> Mn2O2 + NH3 + 2H2O