## 6L.3

KarineKim2L
Posts: 100
Joined: Fri Aug 30, 2019 12:16 am

### 6L.3

For cell diagrams such as the one in problem 6L.3d, how do we know what our half reactions are?

peteryim
Posts: 54
Joined: Sat Sep 07, 2019 12:17 am

### Re: 6L.3

The right side of the diagram will be the cathode; it will be a reduction half reaction. Take whatever ions or substances are given, and make a reduction half reaction from them. The left side will be an anode; it will be an oxidation half reaction. Take whatever ions or substances are given, and make an oxidation half reaction. Balance the amount of electrons required and yielded, and this will give the entire reaction.

san_2F
Posts: 118
Joined: Sat Jul 20, 2019 12:15 am

### Re: 6L.3

I remember being confused on this problem too. What I ended up doing was looking at the reduction half reactions table at Appendix 2A and going from there. I looked at the equations and found which one had O2 and H+ in one equation and O2 and OH- in another equation and manipulated to to result in the right cell diagram.

DHavo_1E
Posts: 118
Joined: Sat Aug 17, 2019 12:17 am

### Re: 6L.3

san_2F wrote:I remember being confused on this problem too. What I ended up doing was looking at the reduction half reactions table at Appendix 2A and going from there. I looked at the equations and found which one had O2 and H+ in one equation and O2 and OH- in another equation and manipulated to to result in the right cell diagram.

Hello,

When finding the oxidation half reaction, could you explain to me how you figured out it was O2(g) + 4H+ (aq) + 4e- -> 2H2O(l), instead of O2 + e- -> O2- ? I'm having trouble understanding what the left side of the cell diagram means (are electrons being given off by oxygen and reacting with hydrogen ions?) Thank you so much!

ValerieChavarin 4F
Posts: 99
Joined: Wed Sep 18, 2019 12:18 am

### Re: 6L.3

You get the half reactions by looking at the species used in the galvanic cell. It helps to think about AnOX RedCat. The left side or anode is where the oxidation reaction occurs (a loss of electrons) and the right is where the reduction occurs (gaining of electrons).