Half Reaction Order

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Veritas Kim 2L
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Joined: Fri Sep 29, 2017 6:05 am

Half Reaction Order

Postby Veritas Kim 2L » Thu Feb 22, 2018 5:58 pm

Does the order matter when we are writing the half reactions as long as we are able to cancel the number of electrons correctly?
If we are writing an oxidation half reaction, does it have to be Zn+ arrow Zn2+ + e-? or can we write it as Zn2+ + e- arrow Zn+ ?

Katie Lam 1B
Posts: 52
Joined: Fri Sep 29, 2017 6:06 am

Re: Half Reaction Order

Postby Katie Lam 1B » Thu Feb 22, 2018 6:21 pm

The placement of the arrow indicates whether oxidation or reduction occurs, so it is important. If it is Zn2+ + 2e- --> Zn, it is reduction since the zinc cation gains electrons. If it is Zn --> Zn2+ + 2e-, it is oxidation since zinc loses electrons.

Charles Ang 1E
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Joined: Thu Jul 13, 2017 2:00 am

Re: Half Reaction Order

Postby Charles Ang 1E » Fri Feb 23, 2018 11:54 pm

It depends on what you are going to do with the half reactions. If you are doing it simply to determine the number of electrons being exchanged or identifying the anode and cathode while finding the standard potential, then the direction of your reactions shouldn't matter.

lindsay lathrop 2C
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Joined: Sat Jul 22, 2017 2:00 am

Re: Half Reaction Order

Postby lindsay lathrop 2C » Sat Feb 24, 2018 2:40 pm

Mathematically it may not matter, however, it would be more correct to keep the equations true to whether it is being reduced or oxidized. Furthermore, it would help you better keep track of what is occurring in a reaction so you can answer any concept related questions more efficiently.

Jennifer Ho 1K
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Joined: Thu Jul 13, 2017 2:00 am

Re: Half Reaction Order

Postby Jennifer Ho 1K » Sun Feb 25, 2018 7:17 pm

The direction does matter, as it determines what forms what in the reaction and whether it is oxidized or reduced.

Jessica Benitez 1K
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Joined: Fri Sep 29, 2017 6:04 am

Re: Half Reaction Order

Postby Jessica Benitez 1K » Sun Feb 25, 2018 9:22 pm

A pattern that I have noticed while doing problems is that when it is an oxidation half reaction the electrons go on the right and when we have a reduction half reaction the electrons are on the left.

Sabah Islam 1G
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Joined: Sat Jul 22, 2017 2:01 am

Re: Half Reaction Order

Postby Sabah Islam 1G » Sun Feb 25, 2018 9:54 pm

The order does matter because the placement of the electron in the half reaction determines whether it is oxidation or reduction. If writing an oxidation reaction, you would write Zn+ arrow Zn2+ + e-, which means that that electrons are being lost, since it is oxidation. If writing a reduction reaction, the electrons would go on the reactants side, since electrons are being gained in reduction.

Abby Ellstrom 1I
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Joined: Fri Sep 29, 2017 6:04 am

Re: Half Reaction Order

Postby Abby Ellstrom 1I » Mon Feb 26, 2018 9:22 pm

The oxidation half reaction includes the electrons on the right side of the arrow.

Veronica Rasmusen 2B
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Joined: Sat Jul 22, 2017 2:01 am

Re: Half Reaction Order

Postby Veronica Rasmusen 2B » Mon Feb 26, 2018 10:27 pm

An oxidation reaction would have the electrons added on the right side of the arrow (electrons are lost) and a reduction reaction would have electrons on the left side (electrons are gained)

Sophia Bozone 2G
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Joined: Fri Sep 29, 2017 6:07 am

Re: Half Reaction Order

Postby Sophia Bozone 2G » Mon Feb 26, 2018 10:50 pm

An oxidation reaction would have the electrons added (electrons are lost), so they should be on the right side of the arrow. A reduction reaction would have the opposite situation occurring, with electrons being gained so they will be listed on the left side.


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