Homework 13.11

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904455068
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Joined: Fri Sep 26, 2014 2:02 pm

Homework 13.11

Postby 904455068 » Sun Feb 08, 2015 3:43 pm

When given cell diagrams, such as part (b) : C(gr)/H2(g)/H+(aq)//Cl-(aq)/Cl2(g)/Pt(s)
How do you determine what each half reaction looks like or better yet, how do you also determine whether they take place at the anode or cathode?

Sarah H Brown 1L
Posts: 56
Joined: Fri Sep 26, 2014 2:02 pm

Re: Homework 13.11

Postby Sarah H Brown 1L » Sun Feb 08, 2015 3:54 pm

Unless specified otherwise, the anode is on the left side of the salt bridge || and the cathode is on the right side of the salt bridge ||.

You determine the half reactions by looking them up on the reference sheet that has half reactions and their standard reduction potentials. Remember, in a galvanic cell, oxidation takes places at the anode (AN OX) and reduction takes place at the cathode (RED CAT). Because you are given reduction potentials, you will have to reverse the half reaction at the anode that you found in the chart to make it the oxidation half reaction.

904455068
Posts: 11
Joined: Fri Sep 26, 2014 2:02 pm

Re: Homework 13.11

Postby 904455068 » Sun Feb 08, 2015 4:03 pm

So without a reference sheet, you wouldn't be able to determine the half reactions?

Sarah H Brown 1L
Posts: 56
Joined: Fri Sep 26, 2014 2:02 pm

Re: Homework 13.11

Postby Sarah H Brown 1L » Sun Feb 08, 2015 4:16 pm

You should be able to. Some are straightforward electron gain. However, the ones that include compounds with oxygen and balanced with H2O and H+ or OH- it is helpful to have the reference sheet.

Justin Le 2I
Posts: 142
Joined: Fri Sep 26, 2014 2:02 pm

Re: Homework 13.11

Postby Justin Le 2I » Tue Feb 10, 2015 12:14 am

Some of them are easy to memorize like H2 -> 2 H+ + 2 e-


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