Reducing agent/oxidizing agent

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Amy Luu 2G
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Joined: Wed Sep 18, 2019 12:19 am

Reducing agent/oxidizing agent

Postby Amy Luu 2G » Sat Feb 22, 2020 6:45 pm

What is the method for determining whether a reactant is a reducing or an oxidizing agent? I am having trouble determining the oxidation number. For the hw problems I determined whether the reactant is an oxidizing or reducing agent by writing the half reactions and seeing which side the electrons are. Is there a way to determine this without writing out the half reactions? For example just looking at the original chemical reaction? Thanks!!

Ariel Davydov 1C
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Re: Reducing agent/oxidizing agent

Postby Ariel Davydov 1C » Sat Feb 22, 2020 7:34 pm

If the oxidation number of an element increases, that means the element is being oxidized (losing electrons) and thus is a reducing agent, since those electrons will be accepted by the element that is being reduced.

If the oxidation number of an element decreases, the element is being reduced and thus is an oxidizing agent, because it accepts the the electrons given up by the element that is being oxidized. Hope this helps!

Emma Popescu 1L
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Re: Reducing agent/oxidizing agent

Postby Emma Popescu 1L » Sat Feb 22, 2020 9:54 pm

The reducing agent is the reactant being oxidized and the oxidizing agent is the reactant being reduced. For most of these reactions, you need to look at the change in oxidation state of the element.

Osvaldo SanchezF -1H
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Re: Reducing agent/oxidizing agent

Postby Osvaldo SanchezF -1H » Sat Feb 22, 2020 10:40 pm

One good way to remember this was by using the acronyms LEO goes GUR where LEO stands for losing electrons is oxidized and GUR stands for Gaining electrons is reduced.

Nicholas_Gladkov_2J
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Re: Reducing agent/oxidizing agent

Postby Nicholas_Gladkov_2J » Sat Feb 22, 2020 11:41 pm

Amy Luu 2G wrote:What is the method for determining whether a reactant is a reducing or an oxidizing agent? I am having trouble determining the oxidation number. For the hw problems I determined whether the reactant is an oxidizing or reducing agent by writing the half reactions and seeing which side the electrons are. Is there a way to determine this without writing out the half reactions? For example just looking at the original chemical reaction? Thanks!!


For the oxidation number it is important to remember a few numbers:
H has the oxidation number +1 (unless attached to a metal, in which it will be -1)
O: -2
F: -1
Li, Na, K, etc. : +1

Then keeping in mind the subscript attached to the element and the overall charge, you can work backwards and find the oxidation number of each element in the reaction. Then if the oxidation number went down, e- were given, so it is the reduction half-reaction and it is the oxidation agent. If the number went up, oxidation half reaction, and it is the reducing agent.

Charlene Datu 2E
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Joined: Wed Sep 11, 2019 12:16 am

Re: Reducing agent/oxidizing agent

Postby Charlene Datu 2E » Sun Feb 23, 2020 12:13 am

I like using the acronym OIL RIG (Oxidation Is Losing electrons; Reduction is Gaining electrons).
If the oxidation number is increasing, it's losing electrons. This means that it's being oxidized.
If the oxidation number is decreasing, it's gaining electrons. This means that it's being reduced.


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