In each of the following reactions, tell which substance is...

In each of the following reactions, tell which substance is undergoing an oxidation and which a reduction, and identify the oxidizing and reducing agents. (a) $\mathrm{Sn} \mathrm{O}_{2}(s)+2 \mathrm{C}(s) \longrightarrow \mathrm{Sn}(s)+2 \mathrm{CO}(g)$ (b) $\mathrm{Sn}^{2+}(a q)+2 \mathrm{Fe}^{3+}(a q) \longrightarrow \mathrm{Sn}^{4+}(a q)+2 \mathrm{Fe}^{2+}(a q)$ (c) $4 \mathrm{NH}_{3}(g)+5 \mathrm{O}_{2}(g) \longrightarrow 4 \mathrm{NO}(g)+6 \mathrm{H}_{2} \mathrm{O}(l)$

In each of the following reactions, tell which substance is undergoing an oxidation and which a reduction, and identify the oxidizing and reducing agents.
(a) $\mathrm{Sn} \mathrm{O}_{2}(s)+2 \mathrm{C}(s) \longrightarrow \mathrm{Sn}(s)+2 \mathrm{CO}(g)$
(b) $\mathrm{Sn}^{2+}(a q)+2 \mathrm{Fe}^{3+}(a q) \longrightarrow \mathrm{Sn}^{4+}(a q)+2 \mathrm{Fe}^{2+}(a q)$
(c) $4 \mathrm{NH}_{3}(g)+5 \mathrm{O}_{2}(g) \longrightarrow 4 \mathrm{NO}(g)+6 \mathrm{H}_{2} \mathrm{O}(l)$

Key Concepts

Oxidation States

Oxidation states, or oxidation numbers, are values assigned to atoms in a compound that indicate the degree of oxidation or reduction relative to a pure element. They are essential tools in redox chemistry for tracking electron transfer and determining which atoms are oxidized or reduced during chemical reactions.

Reducing Agent

The reducing agent is the species that donates electrons during a reaction, leading to the oxidation of another species. Since it loses electrons, the reducing agent undergoes an increase in its oxidation state, making it a critical player in driving the overall electron transfer that occurs in redox processes.

Oxidation

Oxidation is the process in which a substance loses electrons, leading to an increase in its oxidation state. In redox reactions, identifying oxidation helps in understanding which species is donating electrons, thereby undergoing a chemical transformation where its oxidation state becomes higher.

Reduction

Reduction is the process by which a substance gains electrons, resulting in a decrease in its oxidation state. This process indicates that the species is accepting electrons during the reaction, which is fundamental for determining how chemical changes occur in a redox system.

Oxidizing Agent

The oxidizing agent is the substance that accepts electrons during a chemical reaction, causing another species to oxidize. Because it gains electrons in the process, the oxidizing agent itself is reduced, and its capability to facilitate oxidation in other substances is a key aspect of redox chemistry.

Transcript

00:01 Okay, so this question is having us take a look at some redox reactions and decide what our reducing agents are, our oxidizing agents are, and which compounds are being oxidized and reduced.

00:12 So we're going to start with the first one.

00:14 We're taking a look at tin oxide plus carbon to 10 monoxide.

00:33 Okay, so we're going to assign an oxidation number for each of these elements.

00:37 So typically we can assign negative 2 .2.

00:42 To oxygen.

00:43 This is kind of just a rule of thumb there.

00:46 And since there's two oxygens here in order to cancel them out to make the compound zero, 10 has to be a positive 4.

00:55 And then if we take a look at 10 over here, it is by itself, meaning that it automatically gets an oxidation number of zero.

01:05 So we know that 10 has gone from a positive 4 to a neutral 0, meaning that it has lost.

01:14 It has lost its number, meaning it's gained some electrons, meaning it's been reduced.

01:23 And then we take a look here at carbon.

01:27 Carbons by itself, meaning it automatically gets that oxygen number of zero.

01:31 We take a look at carbon over here.

01:35 It is with oxygen, meaning it has to cancel out oxygen, which naturally gets a negative 2, meaning that carbon goes to a positive 2.

01:46 And it's lost some electrons, so it has been oxidized.

01:54 Since anything that's been reduced, typically causes things to be oxidized.

02:00 That means it is the oxidizing agent.

02:08 And since carbon was oxidized, and it's causing something else to be reduced, it is the reducing agent.

02:18 So the answer here is that tin, the sn, is being reduced, sno2 is the oxidizing agent and the carbon is being oxidized and is the reducing agent.

02:51 So that is our first answer.

02:56 Erase that.

02:59 Move on to the next one.

03:03 So our next problem has us take a look at tin and iron.

03:17 So if we take a look at tin and iron, so sn2.

03:32 It's iron.

03:38 This one is a little bit more straightforward because they already give you the charges.

03:49 So we know that 10 is 2 plus.

03:54 And over here, 10 is 4 plus, meaning it has lost some electrons...