cell diagrams: order of components in electrodes?

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Sue Bin Park 2I
Posts: 52
Joined: Mon Jun 17, 2019 7:24 am

cell diagrams: order of components in electrodes?

Postby Sue Bin Park 2I » Sun Mar 01, 2020 1:08 pm

in questions like 6L.5c where you draw cell diagrams given a redox equation:
(c) Cl2(g) 1 H2(g) _> HCl(aq)

how do you know what order each component goes in the anode and cathode? e.g. with the answer:
Pt(s)|H2(g)|H1(aq)||Cl2(aq)|Cl2(g)|Pt(s)
do the gas phases always go on the outsides and aqueous on the inside? i thought it had to do with which component is on the left/right of the redox but this seems to not be the case.

Sjeffrey_1C
Posts: 108
Joined: Wed Feb 20, 2019 12:17 am

Re: cell diagrams: order of components in electrodes?

Postby Sjeffrey_1C » Sun Mar 01, 2020 1:25 pm

Generally it is written as
electrode material (anode) | aqueous solution || aqueous solution | electrode material (cathode)

It seems like the book isn't consistent about this though.

Sofia Ban
Posts: 80
Joined: Fri Sep 28, 2018 12:25 am

Re: cell diagrams: order of components in electrodes?

Postby Sofia Ban » Sun Mar 01, 2020 1:55 pm

anode left; cathode right
-separate anode and cathode with a salt bridge denoted by 2 lines
- separate different states with a single line but if it's the same state but different species, denote it with a comma
- solids are on the outside (solid metal electrode) and if no metal in the reaction, use a solid platinum electrode (Pt(s))
- net is gas, then aqueous should be on both sides of the salt bridge

Cavalli_1H
Posts: 92
Joined: Thu Sep 19, 2019 12:15 am

Re: cell diagrams: order of components in electrodes?

Postby Cavalli_1H » Sun Mar 01, 2020 2:09 pm

my TA said that generally they most likely wouldn't ask a question about cell diagrams on a test because the method in the textbook is inconsistent and we don't really cover a concrete method of approach in lecture. he did say though as a general way of doing it, you should order the diagram as: anode electrode material | gas | aq sol || aq sol | gas | cathode electrode material


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