Cell Diagrams

Joanne Guan 1B
Posts: 30
Joined: Sat Jul 22, 2017 3:01 am

Cell Diagrams

How do you know what goes in what order for a cell diagram? For example, for #14.13 part c, the question gives
Cl2 (g) --> 2Cl- (aq) and
2H+ (aq) --> H2 (g).

Leah Thomas 2E
Posts: 51
Joined: Fri Sep 29, 2017 7:06 am

Re: Cell Diagrams

I'm pretty sure you do the reaction in the anode and then the cathode. Make sure to separate different states with a single line and those with the same states with a comma. A double line goes where the salt bridge is. Do not also forget to add platinum where there is no solid on the anode or cathode side.

Scott Chin_1E
Posts: 55
Joined: Sat Jul 22, 2017 3:00 am

Re: Cell Diagrams

Yes, make sure to determine which reaction is oxidation and reduction. This will help you in determining the order as the cathode (right) is associated with reduction and the anode (left) is associated with oxidation.

Rebecca Doan 2L
Posts: 51
Joined: Thu Jul 27, 2017 3:01 am

Re: Cell Diagrams

Anodes are always on the left and cathodes are always on the right. To figure out which is which you have to determine which reactant is being oxidized and which is being reduced, so look at the electrons.

Katherine Jordak 1H
Posts: 51
Joined: Fri Sep 29, 2017 7:05 am

Re: Cell Diagrams

In a galvanic cell, Ecell is always greater than zero. When you are given two half equations, determine in which reaction the reactant is being oxidized and in which reaction the reactant is being reduced. In problem 14.13 part c in the first half reaction, Cl's oxidation number goes from 0 to 1-. Therefore, we know Cl is being oxidized (it gained electrons). In the second half reaction, H's oxidation number goes from 0 to 1+. Therefore, we know H is being reduced (it lost electrons). Oxidation happens at the anode, so we know the first half reaction will go on the left side of the cell diagram. Reduction happens at the cathode, so we know the second half reaction will go on the right of the cell diagram.