Specify which of the following equations represent...

Specify which of the following equations represent oxidation–reduction reactions, and indicate the oxidizing agent, the reducing agent, the species being oxidized, and the species being reduced. a. $\mathrm{CH}_{4}(g)+\mathrm{H}_{2} \mathrm{O}(g) \rightarrow \mathrm{CO}(g)+3 \mathrm{H}_{2}(g)$ b. $2 \mathrm{AgNO}_{3}(a q)+\mathrm{Cu}(s) \rightarrow \mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}(a q)+2 \mathrm{Ag}(s)$ c. $\mathrm{Zn}(s)+2 \mathrm{HCl}(a q) \rightarrow \mathrm{ZnCl}_{2}(a q)+\mathrm{H}_{2}(g)$ d. $2 \mathrm{H}^{+}(a q)+2 \mathrm{CrO}_{4}^{2-}(a q) \rightarrow \mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}(a q)+\mathrm{H}_{2} \mathrm{O}(l)$

Specify which of the following equations represent oxidation–reduction reactions, and indicate the oxidizing agent, the reducing agent, the species being oxidized, and the species being reduced.
a. $\mathrm{CH}_{4}(g)+\mathrm{H}_{2} \mathrm{O}(g) \rightarrow \mathrm{CO}(g)+3 \mathrm{H}_{2}(g)$
b. $2 \mathrm{AgNO}_{3}(a q)+\mathrm{Cu}(s) \rightarrow \mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}(a q)+2 \mathrm{Ag}(s)$
c. $\mathrm{Zn}(s)+2 \mathrm{HCl}(a q) \rightarrow \mathrm{ZnCl}_{2}(a q)+\mathrm{H}_{2}(g)$
d. $2 \mathrm{H}^{+}(a q)+2 \mathrm{CrO}_{4}^{2-}(a q) \rightarrow \mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}(a q)+\mathrm{H}_{2} \mathrm{O}(l)$

Key Concepts

Oxidation

Oxidation is the process where a chemical species loses electrons, leading to an increase in its oxidation state. This concept is central to understanding how electron transfers drive chemical transformations in redox reactions.

Reduction

Reduction is the process where a chemical species gains electrons, resulting in a decrease in its oxidation state. Recognizing reduction helps identify which reaction components are acquiring electrons during a redox process.

Oxidizing Agent

The oxidizing agent is the species that accepts electrons during a redox reaction, thereby causing another species to be oxidized. It is reduced in the process, making its identification key to understanding redox reaction mechanisms.

Reducing Agent

The reducing agent is the species that donates electrons in a redox reaction, leading to the oxidation of another species. This concept is important because it highlights the source of electrons in the reaction.

Redox Reaction Identification

Redox reactions are characterized by the transfer of electrons between chemical species, resulting in changes in oxidation numbers. This concept involves comparing the oxidation states before and after a reaction to determine which species are oxidized and which are reduced.

Transcript

00:03 Hello.

00:04 My name is margaret, and today i'm going to help you guys with problem 19 from chapter 18 of the zoomdoll book.

00:13 And it's essentially given us four different chemical reactions.

00:19 And it's asking us to identify which of them is, which of them are redox reactions and indicate the oxidizing agent, reducing agents.

00:32 What's being oxidized and what's being reduced.

00:35 Now, it's a little tricky to me because my answer guide tells me that there's only one correct answer here, and that's incorrect.

00:49 Multiple of these reactions are redox reactions.

00:54 And so what i'm going to do for you guys is i'm going to go through each of the individual reactions here, show you what i see and identify everything.

01:07 And you can go to your professor or your teacher and talk it out with them exactly what's going on.

01:16 Or if you have online homework, you can kind of, you know, pick and choose what you want to follow.

01:22 But i really wasn't sure why that was the case.

01:32 That disclaimer being said, let's get started.

01:37 So this first reaction is definitely non -traditional, especially for this chapter where all they really do is cover metallic redox reactions.

01:52 But redox reactions are absolutely, absolutely happen with organic compounds.

01:59 And the rules of thumb here are, and you learn them more in depth than organic chemistry, but essentially it's all about hydrogens and oxygens.

02:12 And so if you add, so let's create a little bit of a table.

02:23 So for reduction, you have hydrogen and you have oxygen, and then you have oxidation, if i could spell.

02:39 Sorry? all right.

02:45 All right.

02:47 So for reduction, okay, you are either going to add hydrogen or you are going to lose oxygen.

03:04 That's how you know a reduction act of reaction is happening.

03:09 If this in oxidation, then the opposite is true.

03:13 You are either losing hydrogen or you are adding oxygen.

03:19 And when we say losing or adding, this is typically focused around the carbon species.

03:36 And if there's more than one, then typically the carbon species of focus or largest.

03:48 And it's usually pretty clear which one that is.

03:53 Especially in a combustion.

03:55 Combustion reactions are always oxidations and it's really clear then because it's almost always just one carbon molecule plus oxygen equals other stuff.

04:06 So here we're going to focus on this molecule right here, which is methane, plus water equals carbon monoxide and hydrogen.

04:17 So here it initially our carbon molecule or our carbon atom initially has four hydrogen.

04:25 Found to it.

04:27 And then over on this side, okay? it has not only no more hydrogens, it's had an oxygen added to it.

04:36 So going over here to our table, not only has it lost hydrogen, it's added oxygen, which means that an oxidation has occurred to that carbon molecule.

04:50 So that means that oxidation has occurred here.

05:00 And so if this underwent oxidation, then the water was reduced.

05:08 Whoops, that's too high up.

05:12 So this was reduced.

05:21 And so something peculiar about reducing agents and oxidizing agents is that they are always on the product side of the reaction.

05:30 And so whatever has been oxidized always ends up being the reducing agents.

05:39 Agent.

05:39 So the carbon monoxide is our reducing agent.

05:57 And so the hydrogen ends up being our oxidizing.

06:15 And so that is how i would label this problem.

06:19 Moving on to b, here we start looking at some more traditional chemistry.

06:32 All right.