Separating the equation

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Miriam Sheetz 2B
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Joined: Fri Sep 28, 2018 12:25 am

Separating the equation

Postby Miriam Sheetz 2B » Wed Feb 20, 2019 3:28 pm

Today in class Dr. Lavelle discussed it may be easier to figure out redox rxns by separating the equation. Can someone explain what he meant by this I am still confused?

Ashley Zhu 1A
Posts: 69
Joined: Fri Sep 28, 2018 12:16 am

Re: Separating the equation

Postby Ashley Zhu 1A » Wed Feb 20, 2019 3:42 pm

by separating the equation, Dr. Lavelle means that you should separate the oxidation part from the reduction part

for example, if you have the equation Cu2+ + Zn --> Cu + Zn2+ you can separate the Cu's and Zn's to get Cu2+ + 2e- --> Cu (reduction) and Zn --> Zn2+ + 2e- (oxidation) (you don't see the two 2e-'s in the original equation because they cancel out if you add the two equations together)
this way, you're clearly able to see which species was reduced (which one gained e-s) and which species was oxidized (lost e-s)

hope this helps

Dhwani Krishnan 1G
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Joined: Fri Sep 28, 2018 12:17 am

Re: Separating the equation

Postby Dhwani Krishnan 1G » Wed Feb 20, 2019 4:11 pm

Why would you separate the equation? Like how would this make it easier?

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Joined: Fri Sep 28, 2018 12:22 am

Re: Separating the equation

Postby Felicia1E » Wed Feb 20, 2019 4:20 pm

The separated reactions are called half-reactions, and they generally help you visualize the transfer of electrons with respect to oxidation and reduction. For balancing equations, people who are really familiar with these reactions could figure out how to balance the charges and mols of elements inside their heads, but generally, using half reactions and writing them down helps you keep track of your work.

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Joined: Fri Sep 28, 2018 12:23 am

Re: Separating the equation

Postby hazelyang2E » Wed Feb 20, 2019 4:27 pm

You separate the equations into two half reactions because it is easier to see which compounds are being reduced and which ones are being oxidized. When you separate the reaction into two reactions it is also easier to balance out the equations and clearly see where electrons are being lost or gained during the overall reaction.

JiangJC Dis2K
Posts: 72
Joined: Fri Oct 12, 2018 12:16 am

Re: Separating the equation

Postby JiangJC Dis2K » Wed Feb 20, 2019 4:38 pm

Basically you're going to want to identify which element is reduced and which is oxidized and then write out separate equations. Therefore, you would write one equation for the reduction and another equation for the oxidation. By balancing both with the electrons cancelling out, you therefore have a full balanced redox reaction. Think of it a little like delta H in thermochemistry in which equations were reversed, multiplied, or divided to cancel out for an overall reaction. I'm guessing this will eventually tie into determining total E values :)

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