[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:02.58,Default,,0000,0000,0000,,Let's figure out the oxidation states
Dialogue: 0,0:00:02.64,0:00:05.44,Default,,0000,0000,0000,,for some more constituent atoms and molecules.
Dialogue: 0,0:00:05.49,0:00:11.83,Default,,0000,0000,0000,,So let's say I had magnesium oxide.
Dialogue: 0,0:00:11.84,0:00:14.49,Default,,0000,0000,0000,,MgO.
Dialogue: 0,0:00:14.57,0:00:16.57,Default,,0000,0000,0000,,I'll do oxygen in a different color.
Dialogue: 0,0:00:16.58,0:00:18.97,Default,,0000,0000,0000,,So what are going to be their oxidation states?
Dialogue: 0,0:00:18.98,0:00:20.19,Default,,0000,0000,0000,,And you might know this already,
Dialogue: 0,0:00:20.20,0:00:21.57,Default,,0000,0000,0000,,but let's look at the periodic table,
Dialogue: 0,0:00:21.58,0:00:23.70,Default,,0000,0000,0000,,because it never hurts to get familiar with it.
Dialogue: 0,0:00:23.72,0:00:24.73,Default,,0000,0000,0000,,So we have magnesium.
Dialogue: 0,0:00:24.74,0:00:27.84,Default,,0000,0000,0000,,Magnesium has two valance electrons.
Dialogue: 0,0:00:27.94,0:00:29.24,Default,,0000,0000,0000,,It's a Group 2 element.
Dialogue: 0,0:00:29.26,0:00:32.27,Default,,0000,0000,0000,,It would love to lose those two electrons.
Dialogue: 0,0:00:32.29,0:00:34.12,Default,,0000,0000,0000,,Oxygen, we already know,
Dialogue: 0,0:00:34.13,0:00:36.96,Default,,0000,0000,0000,,is one of the most electronegative atoms.
Dialogue: 0,0:00:36.98,0:00:38.48,Default,,0000,0000,0000,,It's so electronegative that
Dialogue: 0,0:00:38.49,0:00:42.08,Default,,0000,0000,0000,,oxidized has essentially been named after them.
Dialogue: 0,0:00:42.13,0:00:45.62,Default,,0000,0000,0000,,And we know that oxygen loves to gain two electrons.
Dialogue: 0,0:00:45.64,0:00:47.70,Default,,0000,0000,0000,,So this is kind of a marriage made in heaven.
Dialogue: 0,0:00:47.74,0:00:49.34,Default,,0000,0000,0000,,This guy wants to lose two electrons
Dialogue: 0,0:00:49.35,0:00:51.98,Default,,0000,0000,0000,,and this guy wants to gain two electrons.
Dialogue: 0,0:00:52.01,0:00:53.97,Default,,0000,0000,0000,,So what's going to happen?
Dialogue: 0,0:00:53.98,0:00:57.34,Default,,0000,0000,0000,,The magnesium is going to lose two electrons.
Dialogue: 0,0:00:57.35,0:00:58.92,Default,,0000,0000,0000,,It was neutral.
Dialogue: 0,0:00:58.93,0:01:03.10,Default,,0000,0000,0000,,So it's going to have a plus 2 charge, hypothetically.
Dialogue: 0,0:01:03.12,0:01:06.80,Default,,0000,0000,0000,,And then, the oxygen is going to have a minus 2 charge,
Dialogue: 0,0:01:06.81,0:01:08.99,Default,,0000,0000,0000,,because it gained the two electrons.
Dialogue: 0,0:01:09.00,0:01:13.41,Default,,0000,0000,0000,,So in this molecule of magnesium oxide,
Dialogue: 0,0:01:13.43,0:01:17.62,Default,,0000,0000,0000,,the oxidation state of magnesium is plus 2.
Dialogue: 0,0:01:17.63,0:01:22.56,Default,,0000,0000,0000,,And the oxidation state of the oxygen is minus 2.
Dialogue: 0,0:01:22.57,0:01:25.78,Default,,0000,0000,0000,,Now let's do a slightly harder one.
Dialogue: 0,0:01:25.80,0:01:34.59,Default,,0000,0000,0000,,Let's say we had magnesium hydroxide.
Dialogue: 0,0:01:34.61,0:01:40.79,Default,,0000,0000,0000,,So hydroxide is OH2.
Dialogue: 0,0:01:40.81,0:01:45.05,Default,,0000,0000,0000,,OH2 right there, where there's two hydroxide groups in this.
Dialogue: 0,0:01:45.07,0:01:49.19,Default,,0000,0000,0000,,So, my temptation would still be, look.
Dialogue: 0,0:01:49.20,0:01:52.62,Default,,0000,0000,0000,,Magnesium likes to lose its electrons, its two electrons,
Dialogue: 0,0:01:52.64,0:01:54.81,Default,,0000,0000,0000,,which would make it's charge positive
Dialogue: 0,0:01:54.82,0:01:57.12,Default,,0000,0000,0000,,-- it's hypothetical oxidation state positive.
Dialogue: 0,0:01:57.13,0:01:59.30,Default,,0000,0000,0000,,So my temptation is to say,
Dialogue: 0,0:01:59.32,0:02:01.09,Default,,0000,0000,0000,,hey, magnesium here would be plus 2.
Dialogue: 0,0:02:01.10,0:02:02.19,Default,,0000,0000,0000,,So let me write that there.
Dialogue: 0,0:02:02.21,0:02:06.07,Default,,0000,0000,0000,,And remember, in order for everything to work out,
Dialogue: 0,0:02:06.09,0:02:08.22,Default,,0000,0000,0000,,if it's a neutral compound,
Dialogue: 0,0:02:08.23,0:02:11.97,Default,,0000,0000,0000,,all of the oxidation states in it have to add up to 1.
Dialogue: 0,0:02:11.99,0:02:13.47,Default,,0000,0000,0000,,So let's see if that's going to work out.
Dialogue: 0,0:02:13.49,0:02:14.92,Default,,0000,0000,0000,,Now, oxygen.
Dialogue: 0,0:02:14.93,0:02:17.74,Default,,0000,0000,0000,,My impulse is that its oxidation state
Dialogue: 0,0:02:17.75,0:02:19.91,Default,,0000,0000,0000,,tends to be minus 2.
Dialogue: 0,0:02:19.93,0:02:21.26,Default,,0000,0000,0000,,So let me write that down.
Dialogue: 0,0:02:21.27,0:02:23.19,Default,,0000,0000,0000,,Minus 2.
Dialogue: 0,0:02:23.20,0:02:27.24,Default,,0000,0000,0000,,And hydrogen, when it's bonded with an oxygen
Dialogue: 0,0:02:27.25,0:02:28.48,Default,,0000,0000,0000,,-- remember. In this case, the hydrogen is bonded
Dialogue: 0,0:02:28.49,0:02:29.94,Default,,0000,0000,0000,,with the oxygen first.
Dialogue: 0,0:02:29.96,0:02:32.35,Default,,0000,0000,0000,,And then that's bonded to the magnesium.
Dialogue: 0,0:02:32.36,0:02:35.37,Default,,0000,0000,0000,,So the hydrogen is bonded to an oxygen.
Dialogue: 0,0:02:35.39,0:02:38.36,Default,,0000,0000,0000,,Hydrogen, if it was bonded to a magnesium,
Dialogue: 0,0:02:38.37,0:02:39.53,Default,,0000,0000,0000,,you might want to say, hey,
Dialogue: 0,0:02:39.55,0:02:40.63,Default,,0000,0000,0000,,maybe it'll take the electrons
Dialogue: 0,0:02:40.64,0:02:43.17,Default,,0000,0000,0000,,and it'll have a negative oxidation state.
Dialogue: 0,0:02:43.18,0:02:45.94,Default,,0000,0000,0000,,But when hydrogen is bonded with oxygen,
Dialogue: 0,0:02:45.99,0:02:47.53,Default,,0000,0000,0000,,it gives up the electrons.
Dialogue: 0,0:02:47.55,0:02:51.34,Default,,0000,0000,0000,,It only has one electron to give up.
Dialogue: 0,0:02:51.35,0:02:53.92,Default,,0000,0000,0000,,So it has a plus 1 oxidation state.
Dialogue: 0,0:02:53.93,0:02:56.34,Default,,0000,0000,0000,,So let's see. At first, you might say, hey,
Dialogue: 0,0:02:56.35,0:02:58.09,Default,,0000,0000,0000,,I'm adding up the oxidation states.
Dialogue: 0,0:02:58.12,0:03:00.79,Default,,0000,0000,0000,,Plus 2 minus 2 is 0 plus 1.
Dialogue: 0,0:03:00.81,0:03:03.65,Default,,0000,0000,0000,,I get a plus 1 oxidation state here.
Dialogue: 0,0:03:03.67,0:03:05.16,Default,,0000,0000,0000,,That doesn't make sense, Sal.
Dialogue: 0,0:03:05.18,0:03:06.34,Default,,0000,0000,0000,,This is a neutral compound.
Dialogue: 0,0:03:06.35,0:03:08.08,Default,,0000,0000,0000,,And what you to remember is oh, no,
Dialogue: 0,0:03:08.09,0:03:10.26,Default,,0000,0000,0000,,but you have two of these hydroxides right here.
Dialogue: 0,0:03:10.27,0:03:12.15,Default,,0000,0000,0000,,So what you do is you figure out
Dialogue: 0,0:03:12.16,0:03:16.71,Default,,0000,0000,0000,,the sum of the oxidation states of the hydroxide.
Dialogue: 0,0:03:17.39,0:03:20.50,Default,,0000,0000,0000,,So that's minus 2 plus 1.
Dialogue: 0,0:03:20.26,0:03:23.03,Default,,0000,0000,0000,,So for the entire hydroxide molecule,
Dialogue: 0,0:03:23.04,0:03:25.55,Default,,0000,0000,0000,,you have a minus 1 sum.
Dialogue: 0,0:03:25.56,0:03:27.81,Default,,0000,0000,0000,,And then you have two of them. Right?
Dialogue: 0,0:03:27.83,0:03:30.07,Default,,0000,0000,0000,,You have two hydroxide molecules here.
Dialogue: 0,0:03:30.08,0:03:34.69,Default,,0000,0000,0000,,So the contribution to the entire compound's
Dialogue: 0,0:03:34.71,0:03:37.38,Default,,0000,0000,0000,,oxidation state will be minus 1 for each hydroxide.
Dialogue: 0,0:03:37.39,0:03:39.46,Default,,0000,0000,0000,,But then you have two of them.
Dialogue: 0,0:03:39.47,0:03:43.30,Default,,0000,0000,0000,,So it's minus 2 and then plus 2 from the magnesium.
Dialogue: 0,0:03:43.31,0:03:45.26,Default,,0000,0000,0000,,And it all adds up to 0.
Dialogue: 0,0:03:45.28,0:03:47.06,Default,,0000,0000,0000,,So that worked out.
Dialogue: 0,0:03:47.08,0:03:49.47,Default,,0000,0000,0000,,Now, I want to do a little bit of an aside.
Dialogue: 0,0:03:49.48,0:03:51.40,Default,,0000,0000,0000,,I want to go back to doing some problems again.
Dialogue: 0,0:03:51.42,0:03:52.93,Default,,0000,0000,0000,,But I want to do a little bit of an aside
Dialogue: 0,0:03:52.94,0:03:54.48,Default,,0000,0000,0000,,on some of my terminology.
Dialogue: 0,0:03:54.53,0:03:57.06,Default,,0000,0000,0000,,Because I've kind of used oxidation state, and oxidized,
Dialogue: 0,0:03:57.08,0:04:00.89,Default,,0000,0000,0000,,and reduced interchangeably, to a certain degree.
Dialogue: 0,0:04:00.91,0:04:04.27,Default,,0000,0000,0000,,But, we've done so many problems with water
Dialogue: 0,0:04:04.28,0:04:07.20,Default,,0000,0000,0000,,with water autoionizing into
Dialogue: 0,0:04:07.22,0:04:10.04,Default,,0000,0000,0000,,-- actually, let me do 2 moles of water.
Dialogue: 0,0:04:10.05,0:04:12.02,Default,,0000,0000,0000,,And it's in equilibrium
Dialogue: 0,0:04:12.03,0:04:20.09,Default,,0000,0000,0000,,with 1 mole of H30 plus OH minus.
Dialogue: 0,0:04:20.11,0:04:22.28,Default,,0000,0000,0000,,And obviously, everything is in an aqueous solution.
Dialogue: 0,0:04:22.29,0:04:24.35,Default,,0000,0000,0000,,Now, let's look at the water.
Dialogue: 0,0:04:24.36,0:04:25.97,Default,,0000,0000,0000,,What are the oxidation states in this water right here?
Dialogue: 0,0:04:25.99,0:04:28.78,Default,,0000,0000,0000,,Well, we've done this already in the previous video.
Dialogue: 0,0:04:28.79,0:04:31.04,Default,,0000,0000,0000,,Oxidation state of oxygen is minus 2,
Dialogue: 0,0:04:31.05,0:04:34.11,Default,,0000,0000,0000,,because it's hogging the two electrons from the two hydrogens.
Dialogue: 0,0:04:34.14,0:04:36.94,Default,,0000,0000,0000,,Each hydrogen is giving up an electron.
Dialogue: 0,0:04:36.95,0:04:38.89,Default,,0000,0000,0000,,So it has an oxidation state of plus 1.
Dialogue: 0,0:04:38.90,0:04:40.57,Default,,0000,0000,0000,,And we see this molecule.
Dialogue: 0,0:04:40.59,0:04:41.60,Default,,0000,0000,0000,,Everything adds up.
Dialogue: 0,0:04:41.61,0:04:43.73,Default,,0000,0000,0000,,Because you have two hydrogens with a plus 1.
Dialogue: 0,0:04:43.74,0:04:44.83,Default,,0000,0000,0000,,So that's plus 2.
Dialogue: 0,0:04:44.84,0:04:48.38,Default,,0000,0000,0000,,Plus 2 minus 2 for that one oxygen, and you get to 0.
Dialogue: 0,0:04:48.40,0:04:49.63,Default,,0000,0000,0000,,And it's a neutral compound.
Dialogue: 0,0:04:49.64,0:04:51.95,Default,,0000,0000,0000,,Now here, what are the oxidation states?
Dialogue: 0,0:04:51.96,0:04:56.42,Default,,0000,0000,0000,,So one of these hydrogens left one of these water molecules
Dialogue: 0,0:04:56.43,0:05:00.61,Default,,0000,0000,0000,,and joined the other of the water molecules
Dialogue: 0,0:05:00.63,0:05:02.13,Default,,0000,0000,0000,,without taking its electron with it.
Dialogue: 0,0:05:02.14,0:05:04.21,Default,,0000,0000,0000,,So it left the electron over here.
Dialogue: 0,0:05:04.22,0:05:08.94,Default,,0000,0000,0000,,So that oxygen still has a minus 2 oxidation state.
Dialogue: 0,0:05:08.96,0:05:12.01,Default,,0000,0000,0000,,And this hydrogen still has a plus 1.
Dialogue: 0,0:05:12.02,0:05:15.23,Default,,0000,0000,0000,,And that's why you do minus 2 plus 1.
Dialogue: 0,0:05:15.24,0:05:16.37,Default,,0000,0000,0000,,You get minus 1.
Dialogue: 0,0:05:16.38,0:05:17.91,Default,,0000,0000,0000,,And this time, it works out,
Dialogue: 0,0:05:17.93,0:05:20.01,Default,,0000,0000,0000,,because that's the actual charge on this hydroxide ion.
Dialogue: 0,0:05:20.02,0:05:22.68,Default,,0000,0000,0000,,Now, here, what are the oxidation states?
Dialogue: 0,0:05:22.69,0:05:28.17,Default,,0000,0000,0000,,Each of the hydrogens have a plus 1 oxidation state.
Dialogue: 0,0:05:28.19,0:05:30.80,Default,,0000,0000,0000,,And then this oxygen has a minus 2.
Dialogue: 0,0:05:30.81,0:05:34.44,Default,,0000,0000,0000,,And so if you look at the charge for the entire molecule,
Dialogue: 0,0:05:34.45,0:05:37.41,Default,,0000,0000,0000,,plus 1 on three hydrogens, so that's plus 3.
Dialogue: 0,0:05:37.42,0:05:39.78,Default,,0000,0000,0000,,I just added them up.
Dialogue: 0,0:05:39.80,0:05:40.81,Default,,0000,0000,0000,,Minus 2.
Dialogue: 0,0:05:40.83,0:05:44.89,Default,,0000,0000,0000,,So plus 3 minus 2, I should have a plus 1 charge
Dialogue: 0,0:05:44.90,0:05:47.05,Default,,0000,0000,0000,,on this entire molecule, which is the case.
Dialogue: 0,0:05:47.07,0:05:48.90,Default,,0000,0000,0000,,Now, my question to you is
Dialogue: 0,0:05:48.92,0:05:52.86,Default,,0000,0000,0000,,has any of the oxidation states changed for any of the atoms?
Dialogue: 0,0:05:52.88,0:05:54.45,Default,,0000,0000,0000,,All of the hydrogens here
Dialogue: 0,0:05:54.46,0:05:58.13,Default,,0000,0000,0000,,-- and we could call this 2 moles of water.
Dialogue: 0,0:05:58.14,0:06:00.45,Default,,0000,0000,0000,,Or maybe I just have two molecules of water.
Dialogue: 0,0:06:00.46,0:06:02.12,Default,,0000,0000,0000,,But I have four hydrogens here.
Dialogue: 0,0:06:02.14,0:06:04.68,Default,,0000,0000,0000,,Right? And all of them had an oxidation state of 1.
Dialogue: 0,0:06:04.69,0:06:07.04,Default,,0000,0000,0000,,On the right-hand side, I have four hydrogens.
Dialogue: 0,0:06:07.05,0:06:09.46,Default,,0000,0000,0000,,All of them have an oxidation state of 1.
Dialogue: 0,0:06:09.47,0:06:13.58,Default,,0000,0000,0000,,So although their oxidation state is 1, in this reaction
Dialogue: 0,0:06:13.60,0:06:16.49,Default,,0000,0000,0000,,-- and you can pick either direction of the reaction--
Dialogue: 0,0:06:16.50,0:06:19.25,Default,,0000,0000,0000,,hydrogen has not been oxidized.
Dialogue: 0,0:06:19.29,0:06:21.98,Default,,0000,0000,0000,,Its oxidation state did not change.
Dialogue: 0,0:06:22.00,0:06:26.41,Default,,0000,0000,0000,,Maybe it was oxidized in a previous reaction
Dialogue: 0,0:06:26.42,0:06:27.84,Default,,0000,0000,0000,,where the water was formed,
Dialogue: 0,0:06:27.85,0:06:29.91,Default,,0000,0000,0000,,but in this reaction, it was not oxidized.
Dialogue: 0,0:06:29.93,0:06:31.87,Default,,0000,0000,0000,,Likewise, the oxygens
Dialogue: 0,0:06:31.88,0:06:35.08,Default,,0000,0000,0000,,-- we have two oxygen molecules, or atoms, here.
Dialogue: 0,0:06:35.09,0:06:37.61,Default,,0000,0000,0000,,Each have a minus 2 oxidation state.
Dialogue: 0,0:06:37.62,0:06:39.52,Default,,0000,0000,0000,,Here, we have two oxygen molecules.
Dialogue: 0,0:06:39.53,0:06:41.39,Default,,0000,0000,0000,,Each have a minus 2 oxidation state.
Dialogue: 0,0:06:41.40,0:06:43.65,Default,,0000,0000,0000,,Due to this reaction, at least,
Dialogue: 0,0:06:43.66,0:06:48.21,Default,,0000,0000,0000,,no electrons changed hands in our oxidation state world.
Dialogue: 0,0:06:48.23,0:06:52.31,Default,,0000,0000,0000,,So this is not an oxidation or a reduction reaction.
Dialogue: 0,0:06:52.33,0:06:54.41,Default,,0000,0000,0000,,And I'm going to cover that in detail in the next video.
Dialogue: 0,0:06:54.42,0:06:55.53,Default,,0000,0000,0000,,And I just want to be clear that
Dialogue: 0,0:06:55.55,0:06:58.00,Default,,0000,0000,0000,,nothing here was oxidized or reduced,
Dialogue: 0,0:06:58.02,0:07:02.57,Default,,0000,0000,0000,,because their oxidation states stayed the same.
Dialogue: 0,0:07:02.60,0:07:08.17,Default,,0000,0000,0000,,Because sometimes I'll say, hey, look.
Dialogue: 0,0:07:08.19,0:07:10.23,Default,,0000,0000,0000,,Magnesium has an oxidation state of plus 2.
Dialogue: 0,0:07:10.25,0:07:13.37,Default,,0000,0000,0000,,And oxygen has an oxidation state of minus 2.
Dialogue: 0,0:07:13.39,0:07:15.40,Default,,0000,0000,0000,,Magnesium was oxidized.
Dialogue: 0,0:07:15.42,0:07:16.96,Default,,0000,0000,0000,,Two electrons were taken away from it.
Dialogue: 0,0:07:16.98,0:07:18.74,Default,,0000,0000,0000,,And oxygen was reduced.
Dialogue: 0,0:07:18.75,0:07:20.24,Default,,0000,0000,0000,,Two electrons were given to it.
Dialogue: 0,0:07:20.26,0:07:22.92,Default,,0000,0000,0000,,And I'll say that implying some reaction that produced it,
Dialogue: 0,0:07:22.93,0:07:24.61,Default,,0000,0000,0000,,but that's not always the case.
Dialogue: 0,0:07:24.62,0:07:25.82,Default,,0000,0000,0000,,You could have a reaction
Dialogue: 0,0:07:25.83,0:07:27.54,Default,,0000,0000,0000,,where that necessarily didn't happen.
Dialogue: 0,0:07:27.57,0:07:29.55,Default,,0000,0000,0000,,But the oxidation state for magnesium
Dialogue: 0,0:07:29.56,0:07:30.93,Default,,0000,0000,0000,,is definitely plus 2.
Dialogue: 0,0:07:30.94,0:07:34.21,Default,,0000,0000,0000,,And the oxidation state for the oxygen,
Dialogue: 0,0:07:34.23,0:07:36.89,Default,,0000,0000,0000,,or the oxidation number, is minus 2.
Dialogue: 0,0:07:36.90,0:07:38.86,Default,,0000,0000,0000,,But I think you know what I'm talking about
Dialogue: 0,0:07:38.87,0:07:40.30,Default,,0000,0000,0000,,when I say it was oxidized.
Dialogue: 0,0:07:40.31,0:07:43.08,Default,,0000,0000,0000,,At some point, it went from a neutral magnesium
Dialogue: 0,0:07:43.10,0:07:45.77,Default,,0000,0000,0000,,to a positively charged magnesium
Dialogue: 0,0:07:45.79,0:07:47.14,Default,,0000,0000,0000,,by losing two electrons.
Dialogue: 0,0:07:47.16,0:07:48.55,Default,,0000,0000,0000,,So it got oxidized.
Dialogue: 0,0:07:48.57,0:07:52.15,Default,,0000,0000,0000,,Now, let's do some harder problems.
Dialogue: 0,0:07:52.16,0:07:53.98,Default,,0000,0000,0000,,So hydrogen peroxide
Dialogue: 0,0:07:53.99,0:07:56.29,Default,,0000,0000,0000,,-- I've said multiple times already that
Dialogue: 0,0:07:56.30,0:08:01.44,Default,,0000,0000,0000,,oxygen tends to have a minus 2 oxidation state.
Dialogue: 0,0:08:01.45,0:08:02.67,Default,,0000,0000,0000,,This is minus 1.
Dialogue: 0,0:08:02.68,0:08:06.34,Default,,0000,0000,0000,,I think you see the pattern. These guys are plus 1.
Dialogue: 0,0:08:06.35,0:08:08.59,Default,,0000,0000,0000,,Hydrogen is plus or minus 1.
Dialogue: 0,0:08:08.60,0:08:10.56,Default,,0000,0000,0000,,These guys are plus 2.
Dialogue: 0,0:08:10.57,0:08:11.84,Default,,0000,0000,0000,,I think you see the pattern.
Dialogue: 0,0:08:11.85,0:08:14.16,Default,,0000,0000,0000,,It's whether you want to lose or gain electrons.
Dialogue: 0,0:08:14.17,0:08:16.05,Default,,0000,0000,0000,,You might say, well see,
Dialogue: 0,0:08:16.06,0:08:19.69,Default,,0000,0000,0000,,water normally has a minus 2 oxidation.
Dialogue: 0,0:08:19.70,0:08:21.12,Default,,0000,0000,0000,,So you might be tempted to do
Dialogue: 0,0:08:21.14,0:08:22.25,Default,,0000,0000,0000,,-- OK.
Dialogue: 0,0:08:22.26,0:08:25.19,Default,,0000,0000,0000,,Hydrogen has plus 1, because it's bonding with water.
Dialogue: 0,0:08:25.20,0:08:28.48,Default,,0000,0000,0000,,And oxygen has a minus 2.
Dialogue: 0,0:08:28.49,0:08:31.29,Default,,0000,0000,0000,,But when you do that, you immediately have a conundrum.
Dialogue: 0,0:08:31.31,0:08:32.75,Default,,0000,0000,0000,,This is a neutral molecule
Dialogue: 0,0:08:32.77,0:08:35.41,Default,,0000,0000,0000,,-- let's see. Two hydrogens plus 2.
Dialogue: 0,0:08:35.43,0:08:36.88,Default,,0000,0000,0000,,Two oxygens at minus 2.
Dialogue: 0,0:08:36.89,0:08:37.92,Default,,0000,0000,0000,,Minus 4.
Dialogue: 0,0:08:37.94,0:08:39.47,Default,,0000,0000,0000,,So this would end up with a minus 4
Dialogue: 0,0:08:39.48,0:08:41.51,Default,,0000,0000,0000,,total net oxidation state.
Dialogue: 0,0:08:41.53,0:08:42.86,Default,,0000,0000,0000,,And that's not the case
Dialogue: 0,0:08:42.87,0:08:44.12,Default,,0000,0000,0000,,because this doesn't have any charge.
Dialogue: 0,0:08:44.14,0:08:45.79,Default,,0000,0000,0000,,So there's a conundrum here.
Dialogue: 0,0:08:45.80,0:08:47.48,Default,,0000,0000,0000,,And the conundrum is because,
Dialogue: 0,0:08:47.49,0:08:50.41,Default,,0000,0000,0000,,if you actually look at the structure of hydrogen peroxide,
Dialogue: 0,0:08:50.44,0:08:53.55,Default,,0000,0000,0000,,the oxygens are actually bonded to each other.
Dialogue: 0,0:08:53.57,0:08:55.17,Default,,0000,0000,0000,,That's where the peroxide comes from.
Dialogue: 0,0:08:55.18,0:08:59.63,Default,,0000,0000,0000,,And then each of those are bonded to a hydrogen.
Dialogue: 0,0:08:59.65,0:09:01.72,Default,,0000,0000,0000,,So in this case,
Dialogue: 0,0:09:01.73,0:09:03.96,Default,,0000,0000,0000,,especially in a first-year chemistry course,
Dialogue: 0,0:09:03.97,0:09:07.37,Default,,0000,0000,0000,,the peroxide molecules, especially hydrogen peroxide,
Dialogue: 0,0:09:07.39,0:09:08.84,Default,,0000,0000,0000,,tends to be that one special case.
Dialogue: 0,0:09:08.86,0:09:11.39,Default,,0000,0000,0000,,There are others, but this is the one special case
Dialogue: 0,0:09:11.41,0:09:15.35,Default,,0000,0000,0000,,where oxygen does not have a minus 2 oxidation state.
Dialogue: 0,0:09:15.37,0:09:17.09,Default,,0000,0000,0000,,Let's look at this and try to figure out
Dialogue: 0,0:09:17.10,0:09:18.60,Default,,0000,0000,0000,,what oxygen's oxidation state would be
Dialogue: 0,0:09:18.61,0:09:20.08,Default,,0000,0000,0000,,in hydrogen peroxide.
Dialogue: 0,0:09:20.09,0:09:23.03,Default,,0000,0000,0000,,So in this case, the hydrogen-oxygen bond,
Dialogue: 0,0:09:23.04,0:09:25.27,Default,,0000,0000,0000,,oxygen is going to hog the electron
Dialogue: 0,0:09:25.28,0:09:27.51,Default,,0000,0000,0000,,and hydrogen is going to lose it.
Dialogue: 0,0:09:27.52,0:09:29.00,Default,,0000,0000,0000,,So it's going to have a plus 1 there.
Dialogue: 0,0:09:29.02,0:09:30.04,Default,,0000,0000,0000,,Same thing on the side.
Dialogue: 0,0:09:30.06,0:09:33.16,Default,,0000,0000,0000,,Oxygen, at least on this bond, is going to have a plus 1.
Dialogue: 0,0:09:33.18,0:09:34.41,Default,,0000,0000,0000,,It's going to gain an electron.
Dialogue: 0,0:09:34.42,0:09:36.71,Default,,0000,0000,0000,,What about from this other bond with the other oxygen?
Dialogue: 0,0:09:36.72,0:09:39.66,Default,,0000,0000,0000,,Well, there's no reason why one oxygen should
Dialogue: 0,0:09:39.67,0:09:41.23,Default,,0000,0000,0000,,hog the electron from the other oxygen.
Dialogue: 0,0:09:41.25,0:09:43.85,Default,,0000,0000,0000,,So it's not going to have any net impact
Dialogue: 0,0:09:43.87,0:09:45.00,Default,,0000,0000,0000,,on its oxidation state.
Dialogue: 0,0:09:45.01,0:09:48.00,Default,,0000,0000,0000,,So in this case, this oxygen's oxidation state is plus 1.
Dialogue: 0,0:09:48.01,0:09:52.77,Default,,0000,0000,0000,,This oxygen's oxidation state is also plus 1.
Dialogue: 0,0:09:52.78,0:09:59.40,Default,,0000,0000,0000,,So each of the hydrogens have an oxidation number of plus 1.
Dialogue: 0,0:09:59.42,0:10:03.07,Default,,0000,0000,0000,,You said the oxygens have an oxidation number of minus 1.
Dialogue: 0,0:10:03.09,0:10:05.74,Default,,0000,0000,0000,,And so you have a net of 0.
Dialogue: 0,0:10:05.75,0:10:08.79,Default,,0000,0000,0000,,2 times plus 1, plus 2 times minus 1, is 0.
Dialogue: 0,0:10:08.81,0:10:10.68,Default,,0000,0000,0000,,So that's just a special case.
Dialogue: 0,0:10:10.69,0:10:12.97,Default,,0000,0000,0000,,That's a good one to be familiar with.
Dialogue: 0,0:10:12.98,0:10:14.33,Default,,0000,0000,0000,,Let's do another one.
Dialogue: 0,0:10:14.34,0:10:15.84,Default,,0000,0000,0000,,Iron 3 carbonate.
Dialogue: 0,0:10:15.85,0:10:17.69,Default,,0000,0000,0000,,And now, for the first time
Dialogue: 0,0:10:17.70,0:10:19.97,Default,,0000,0000,0000,,-- I remember when we first encountered iron 3 carbonate.
Dialogue: 0,0:10:19.98,0:10:21.22,Default,,0000,0000,0000,,You probably thought, hey,
Dialogue: 0,0:10:21.23,0:10:22.96,Default,,0000,0000,0000,,why is it called iron 3 carbonate
Dialogue: 0,0:10:22.97,0:10:25.25,Default,,0000,0000,0000,,when there are only two iron molecules,
Dialogue: 0,0:10:25.26,0:10:26.43,Default,,0000,0000,0000,,or two iron atoms, here?
Dialogue: 0,0:10:26.44,0:10:27.82,Default,,0000,0000,0000,,And you're about to learn why.
Dialogue: 0,0:10:27.83,0:10:29.41,Default,,0000,0000,0000,,Let's look at the oxidation numbers.
Dialogue: 0,0:10:29.43,0:10:31.41,Default,,0000,0000,0000,,So oxygen.
Dialogue: 0,0:10:31.42,0:10:35.87,Default,,0000,0000,0000,,Oxygen's oxidation number tends to be minus 2.
Dialogue: 0,0:10:35.89,0:10:38.21,Default,,0000,0000,0000,,Minus 2.
Dialogue: 0,0:10:38.22,0:10:40.65,Default,,0000,0000,0000,,Now, if carbon is bonding with oxygen
Dialogue: 0,0:10:40.67,0:10:42.54,Default,,0000,0000,0000,,-- let's look at the periodic table.
Dialogue: 0,0:10:42.55,0:10:45.68,Default,,0000,0000,0000,,We have carbon bonding with oxygen.
Dialogue: 0,0:10:45.70,0:10:48.51,Default,,0000,0000,0000,,Carbon can go either way.
Dialogue: 0,0:10:48.52,0:10:51.27,Default,,0000,0000,0000,,Carbon, sometimes it likes to give away electrons.
Dialogue: 0,0:10:51.30,0:10:52.87,Default,,0000,0000,0000,,Sometimes it likes to gain electrons.
Dialogue: 0,0:10:52.89,0:10:55.10,Default,,0000,0000,0000,,When carbon is bonding with oxygen,
Dialogue: 0,0:10:55.11,0:10:58.11,Default,,0000,0000,0000,,this right here is the electron hog.
Dialogue: 0,0:10:58.13,0:11:01.14,Default,,0000,0000,0000,,If we had to say who's taking the electrons,
Dialogue: 0,0:11:01.15,0:11:02.67,Default,,0000,0000,0000,,it's going to be oxygen.
Dialogue: 0,0:11:02.68,0:11:03.89,Default,,0000,0000,0000,,Right?
Dialogue: 0,0:11:03.90,0:11:06.86,Default,,0000,0000,0000,,So carbon is going to be giving away its electrons.
Dialogue: 0,0:11:06.87,0:11:09.76,Default,,0000,0000,0000,,But how many electrons can carbon give away?
Dialogue: 0,0:11:09.78,0:11:11.47,Default,,0000,0000,0000,,Well, let's see.
Dialogue: 0,0:11:11.48,0:11:14.99,Default,,0000,0000,0000,,It has 1, 2, 3, 4 valence electrons.
Dialogue: 0,0:11:15.01,0:11:16.07,Default,,0000,0000,0000,,So the most it can really do is
Dialogue: 0,0:11:16.08,0:11:18.56,Default,,0000,0000,0000,,give away four valence electrons.
Dialogue: 0,0:11:18.57,0:11:21.45,Default,,0000,0000,0000,,So let's go back to the carbonate.
Dialogue: 0,0:11:21.46,0:11:26.11,Default,,0000,0000,0000,,So the carbon could at most
Dialogue: 0,0:11:26.12,0:11:29.37,Default,,0000,0000,0000,,give away its four valence electrons.
Dialogue: 0,0:11:29.39,0:11:32.40,Default,,0000,0000,0000,,So what will be the net oxidation number
Dialogue: 0,0:11:32.42,0:11:33.87,Default,,0000,0000,0000,,for the carbonate molecule?
Dialogue: 0,0:11:33.88,0:11:36.39,Default,,0000,0000,0000,,For the CO3?
Dialogue: 0,0:11:36.40,0:11:38.77,Default,,0000,0000,0000,,So this is a plus 4 oxidation,
Dialogue: 0,0:11:38.79,0:11:40.29,Default,,0000,0000,0000,,because it only has four to give away.
Dialogue: 0,0:11:40.30,0:11:42.68,Default,,0000,0000,0000,,If it's bonding with oxygen, it's going to give them away.
Dialogue: 0,0:11:42.69,0:11:43.88,Default,,0000,0000,0000,,Oxygen is more of a hog.
Dialogue: 0,0:11:43.89,0:11:46.27,Default,,0000,0000,0000,,Each oxygen has a minus 2.
Dialogue: 0,0:11:46.28,0:11:48.79,Default,,0000,0000,0000,,So let's think about it.
Dialogue: 0,0:11:48.80,0:11:54.13,Default,,0000,0000,0000,,I have plus 4 minus, 3 times minus 2.
Dialogue: 0,0:11:54.15,0:11:55.21,Default,,0000,0000,0000,,Right?
Dialogue: 0,0:11:55.26,0:11:57.22,Default,,0000,0000,0000,,I have 3 oxygen molecules.
Dialogue: 0,0:11:57.24,0:12:00.35,Default,,0000,0000,0000,,So I have 4 minus 6 is equal to minus 2.
Dialogue: 0,0:12:00.37,0:12:02.85,Default,,0000,0000,0000,,So we can kind of view it as the oxidation number
Dialogue: 0,0:12:02.86,0:12:05.79,Default,,0000,0000,0000,,for the entire carbonate molecule is minus 2.
Dialogue: 0,0:12:05.81,0:12:10.64,Default,,0000,0000,0000,,Now, if this entire carbonate molecule is minus 2,
Dialogue: 0,0:12:10.66,0:12:14.37,Default,,0000,0000,0000,,its contribution to the oxidation state
Dialogue: 0,0:12:14.39,0:12:16.94,Default,,0000,0000,0000,,for this whole kind of
Dialogue: 0,0:12:16.95,0:12:18.73,Default,,0000,0000,0000,,-- the carbonate part of the molecule.
Dialogue: 0,0:12:18.74,0:12:20.63,Default,,0000,0000,0000,,We have 3 carbonate molecules.
Dialogue: 0,0:12:20.64,0:12:22.63,Default,,0000,0000,0000,,Each of them is contributing minus 2.
Dialogue: 0,0:12:22.64,0:12:24.68,Default,,0000,0000,0000,,So I have a minus 6 contribution.
Dialogue: 0,0:12:24.70,0:12:28.36,Default,,0000,0000,0000,,If this is minus 6 and this is a neutral molecule,
Dialogue: 0,0:12:28.38,0:12:32.21,Default,,0000,0000,0000,,then our 2 irons are also going
Dialogue: 0,0:12:32.22,0:12:35.37,Default,,0000,0000,0000,,to have to have a plus 6 oxidation state.
Dialogue: 0,0:12:35.38,0:12:36.82,Default,,0000,0000,0000,,Because it all has to add up to 0.
Dialogue: 0,0:12:36.83,0:12:40.16,Default,,0000,0000,0000,,If both irons combined
Dialogue: 0,0:12:40.18,0:12:43.38,Default,,0000,0000,0000,,have a plus 6 contribution to oxidation state,
Dialogue: 0,0:12:43.40,0:12:46.41,Default,,0000,0000,0000,,then each of the irons must have a plus 3 oxidation.
Dialogue: 0,0:12:46.42,0:12:49.60,Default,,0000,0000,0000,,Or that, in our hypothetical world, if this happens,
Dialogue: 0,0:12:49.62,0:12:52.65,Default,,0000,0000,0000,,at least three electrons are going to
Dialogue: 0,0:12:52.67,0:12:54.80,Default,,0000,0000,0000,,favor the carbonate from each of the irons.
Dialogue: 0,0:12:54.84,0:12:58.12,Default,,0000,0000,0000,,So why is it called iron 3 carbonate?
Dialogue: 0,0:12:58.12,0:13:00.40,Default,,0000,0000,0000,,I think you may have figured this out by now.
Dialogue: 0,0:13:00.42,0:13:04.87,Default,,0000,0000,0000,,Because this is iron in its third oxidation state.
Dialogue: 0,0:13:04.88,0:13:06.07,Default,,0000,0000,0000,,Iron-- a lot of the metals,
Dialogue: 0,0:13:06.09,0:13:07.55,Default,,0000,0000,0000,,especially a lot of the transition metals--
Dialogue: 0,0:13:07.56,0:13:09.56,Default,,0000,0000,0000,,can have multiple oxidation states.
Dialogue: 0,0:13:09.57,0:13:11.29,Default,,0000,0000,0000,,When you have iron 3 carbonate,
Dialogue: 0,0:13:11.30,0:13:12.68,Default,,0000,0000,0000,,you're literally saying,
Dialogue: 0,0:13:12.69,0:13:14.33,Default,,0000,0000,0000,,this is the third oxidation state.
Dialogue: 0,0:13:14.34,0:13:17.81,Default,,0000,0000,0000,,Or iron's oxidation number in this molecule
Dialogue: 0,0:13:17.82,0:13:19.60,Default,,0000,0000,0000,,will be positive 3.
Dialogue: 0,0:13:19.61,0:13:21.94,Default,,0000,0000,0000,,Now, let's do another one.
Dialogue: 0,0:13:21.96,0:13:23.03,Default,,0000,0000,0000,,This is interesting.
Dialogue: 0,0:13:23.05,0:13:24.20,Default,,0000,0000,0000,,Acetic acid.
Dialogue: 0,0:13:24.21,0:13:25.56,Default,,0000,0000,0000,,And I think is the first time that
Dialogue: 0,0:13:25.57,0:13:29.99,Default,,0000,0000,0000,,I've actually shown you the formula for acetic acid.
Dialogue: 0,0:13:30.01,0:13:33.16,Default,,0000,0000,0000,,I won't go into the whole organic chemistry of it.
Dialogue: 0,0:13:33.17,0:13:37.62,Default,,0000,0000,0000,,But let's try to figure out what the different charges are,
Dialogue: 0,0:13:37.64,0:13:39.20,Default,,0000,0000,0000,,or the different oxidation states.
Dialogue: 0,0:13:41.57,0:13:43.28,Default,,0000,0000,0000,,Sometimes you'll just see it written like this.
Dialogue: 0,0:13:43.29,0:13:44.60,Default,,0000,0000,0000,,You'd say, OK.
Dialogue: 0,0:13:44.61,0:13:48.05,Default,,0000,0000,0000,,Oxygens, each of those are going to have minus 2.
Dialogue: 0,0:13:50.92,0:13:53.27,Default,,0000,0000,0000,,Hydrogens are each going to have plus 1.
Dialogue: 0,0:13:56.57,0:13:57.60,Default,,0000,0000,0000,,So how are we doing so far?
Dialogue: 0,0:13:57.63,0:14:01.52,Default,,0000,0000,0000,,So these oxygens are going to contribute minus 4.
Dialogue: 0,0:14:01.54,0:14:03.29,Default,,0000,0000,0000,,And then the hydrogens
Dialogue: 0,0:14:03.30,0:14:08.93,Default,,0000,0000,0000,,-- here you have plus 3. And then here you have plus 1.
Dialogue: 0,0:14:08.95,0:14:12.07,Default,,0000,0000,0000,,You add these up and you get to 0. And you're like, oh.
Dialogue: 0,0:14:12.09,0:14:14.89,Default,,0000,0000,0000,,So the carbons must have no oxidation state.
Dialogue: 0,0:14:14.90,0:14:16.78,Default,,0000,0000,0000,,They must have an oxidation number of 0.
Dialogue: 0,0:14:16.79,0:14:20.48,Default,,0000,0000,0000,,Because we're already at 0,
Dialogue: 0,0:14:20.49,0:14:23.04,Default,,0000,0000,0000,,if we just consider the hydrogens and the oxygens.
Dialogue: 0,0:14:23.05,0:14:25.67,Default,,0000,0000,0000,,So let's look at that and see if that's actually the case.
Dialogue: 0,0:14:25.68,0:14:28.77,Default,,0000,0000,0000,,So when carbon is bonding with hydrogen,
Dialogue: 0,0:14:28.78,0:14:30.23,Default,,0000,0000,0000,,who's going to hog the electrons?
Dialogue: 0,0:14:30.24,0:14:34.67,Default,,0000,0000,0000,,When carbon is bonding with hydrogen.
Dialogue: 0,0:14:34.68,0:14:37.16,Default,,0000,0000,0000,,Electronegativity-- as you go to the right.
Dialogue: 0,0:14:37.17,0:14:39.33,Default,,0000,0000,0000,,Carbon is more electronegative.
Dialogue: 0,0:14:39.35,0:14:42.69,Default,,0000,0000,0000,,It likes to keep the electrons, or hog them,
Dialogue: 0,0:14:42.70,0:14:43.80,Default,,0000,0000,0000,,more than hydrogen.
Dialogue: 0,0:14:43.81,0:14:45.47,Default,,0000,0000,0000,,So hydrogen is going to lose the electrons
Dialogue: 0,0:14:45.48,0:14:46.98,Default,,0000,0000,0000,,in our oxidation state world.
Dialogue: 0,0:14:46.99,0:14:50.60,Default,,0000,0000,0000,,It's actually a covalent bond, but of course,
Dialogue: 0,0:14:50.62,0:14:51.87,Default,,0000,0000,0000,,we know that when we're dealing with oxidation states,
Dialogue: 0,0:14:51.88,0:14:53.26,Default,,0000,0000,0000,,we pretend that it's ionic.
Dialogue: 0,0:14:53.28,0:14:56.62,Default,,0000,0000,0000,,So in this case, your hydrogens are going
Dialogue: 0,0:14:56.63,0:14:58.14,Default,,0000,0000,0000,,to lose electrons.
Dialogue: 0,0:14:58.16,0:15:00.17,Default,,0000,0000,0000,,So they're each going to have an oxidation state of plus 1.
Dialogue: 0,0:15:00.19,0:15:02.94,Default,,0000,0000,0000,,That's consistent with what we know so far.
Dialogue: 0,0:15:02.95,0:15:04.74,Default,,0000,0000,0000,,And actually, that's another thing.
Dialogue: 0,0:15:04.76,0:15:06.68,Default,,0000,0000,0000,,When I did this exercise, right here,
Dialogue: 0,0:15:06.71,0:15:07.75,Default,,0000,0000,0000,,I immediately assumed hydrogen has
Dialogue: 0,0:15:07.76,0:15:10.81,Default,,0000,0000,0000,,an oxidation state of plus 1.
Dialogue: 0,0:15:10.82,0:15:11.85,Default,,0000,0000,0000,,I did that because, oh,
Dialogue: 0,0:15:11.86,0:15:13.62,Default,,0000,0000,0000,,everything else in the molecule is carbon and oxygen,
Dialogue: 0,0:15:13.63,0:15:15.80,Default,,0000,0000,0000,,which are more electronegative than the hydrogen.
Dialogue: 0,0:15:15.81,0:15:17.95,Default,,0000,0000,0000,,So the hydrogen is going to go into its plus 1 state.
Dialogue: 0,0:15:17.96,0:15:19.67,Default,,0000,0000,0000,,If, over here, I had a bunch of
Dialogue: 0,0:15:19.68,0:15:21.50,Default,,0000,0000,0000,,alkali and alkaline earth metals,
Dialogue: 0,0:15:21.52,0:15:22.91,Default,,0000,0000,0000,,I wouldn't be so sure.
Dialogue: 0,0:15:22.93,0:15:24.54,Default,,0000,0000,0000,,I'd say, oh, maybe hydrogen would take electrons from them.
Dialogue: 0,0:15:24.55,0:15:26.47,Default,,0000,0000,0000,,But anyway.
Dialogue: 0,0:15:26.49,0:15:30.27,Default,,0000,0000,0000,,So these all gave an electron to this carbon.
Dialogue: 0,0:15:30.29,0:15:32.27,Default,,0000,0000,0000,,So just from these hydrogens,
Dialogue: 0,0:15:32.29,0:15:39.20,Default,,0000,0000,0000,,that carbon would have a minus 3 oxidation state, right?
Dialogue: 0,0:15:39.22,0:15:41.45,Default,,0000,0000,0000,,These lost electrons.
Dialogue: 0,0:15:41.46,0:15:43.17,Default,,0000,0000,0000,,This guy gained three electrons,
Dialogue: 0,0:15:43.19,0:15:44.62,Default,,0000,0000,0000,,so his charge goes down by 3.
Dialogue: 0,0:15:44.63,0:15:47.45,Default,,0000,0000,0000,,The carbon-carbon bond. Well, there's no reason
Dialogue: 0,0:15:47.47,0:15:49.62,Default,,0000,0000,0000,,one carbon should take electrons from another carbon.
Dialogue: 0,0:15:49.63,0:15:51.40,Default,,0000,0000,0000,,All carbons are created equal.
Dialogue: 0,0:15:51.41,0:15:53.77,Default,,0000,0000,0000,,So there should be no transfer here.
Dialogue: 0,0:15:53.80,0:15:56.12,Default,,0000,0000,0000,,So this carbon's oxidation status is 3.
Dialogue: 0,0:15:56.14,0:15:57.49,Default,,0000,0000,0000,,Now what about on this side?
Dialogue: 0,0:15:57.50,0:16:00.13,Default,,0000,0000,0000,,So we know that this hydrogen is going
Dialogue: 0,0:16:00.14,0:16:02.75,Default,,0000,0000,0000,,to have a plus 1 oxidation state.
Dialogue: 0,0:16:02.77,0:16:04.83,Default,,0000,0000,0000,,It's going to give its electron to this oxygen.
Dialogue: 0,0:16:04.85,0:16:07.88,Default,,0000,0000,0000,,This oxygen, like most oxygens,
Dialogue: 0,0:16:07.89,0:16:09.68,Default,,0000,0000,0000,,are going to take up two electrons.
Dialogue: 0,0:16:09.69,0:16:12.96,Default,,0000,0000,0000,,One from this carbon, and one from this hydrogen.
Dialogue: 0,0:16:12.97,0:16:15.80,Default,,0000,0000,0000,,So it's going to have a minus 2 oxidation state.
Dialogue: 0,0:16:15.81,0:16:19.10,Default,,0000,0000,0000,,This oxygen is also going to take two electrons.
Dialogue: 0,0:16:19.11,0:16:20.70,Default,,0000,0000,0000,,In this case, both of them are going
Dialogue: 0,0:16:20.72,0:16:22.10,Default,,0000,0000,0000,,to be from this orange carbon.
Dialogue: 0,0:16:22.12,0:16:24.49,Default,,0000,0000,0000,,So it's going to have a minus 2 oxidation state.
Dialogue: 0,0:16:24.51,0:16:26.72,Default,,0000,0000,0000,,So what's the oxidation state of this carbon?
Dialogue: 0,0:16:26.73,0:16:30.19,Default,,0000,0000,0000,,It lost two electrons to this guy up here,
Dialogue: 0,0:16:30.20,0:16:35.35,Default,,0000,0000,0000,,and it lost one electron to this oxygen down here.
Dialogue: 0,0:16:35.36,0:16:37.70,Default,,0000,0000,0000,,Remember, this guy got one electron from the carbon
Dialogue: 0,0:16:37.71,0:16:38.83,Default,,0000,0000,0000,,and one from the hydrogen.
Dialogue: 0,0:16:38.84,0:16:41.60,Default,,0000,0000,0000,,So it lost one electron here, two there.
Dialogue: 0,0:16:41.61,0:16:43.39,Default,,0000,0000,0000,,It lost three electrons.
Dialogue: 0,0:16:43.41,0:16:47.57,Default,,0000,0000,0000,,So in that reality, it would have a plus 3 charge.
Dialogue: 0,0:16:47.59,0:16:52.01,Default,,0000,0000,0000,,So it turns out that the average oxidation state
Dialogue: 0,0:16:52.02,0:16:54.99,Default,,0000,0000,0000,,for the carbon in acetic acid is 0.
Dialogue: 0,0:16:55.01,0:16:56.99,Default,,0000,0000,0000,,Because if you average minus 3 and plus 3,
Dialogue: 0,0:16:57.00,0:16:58.30,Default,,0000,0000,0000,,you get to 0.
Dialogue: 0,0:16:58.32,0:17:00.52,Default,,0000,0000,0000,,And that's why I said, oh, maybe these are a 0.
Dialogue: 0,0:17:00.53,0:17:03.18,Default,,0000,0000,0000,,But if you actually write out their oxidation numbers,
Dialogue: 0,0:17:03.20,0:17:07.30,Default,,0000,0000,0000,,this green C has a minus 3 oxidation state.
Dialogue: 0,0:17:07.31,0:17:10.02,Default,,0000,0000,0000,,And this orange C, this orange carbon,
Dialogue: 0,0:17:10.03,0:17:12.64,Default,,0000,0000,0000,,has a plus 3 oxidation state.
Dialogue: 0,0:17:12.66,0:17:14.05,Default,,0000,0000,0000,,If you got this one,
Dialogue: 0,0:17:14.07,0:17:16.06,Default,,0000,0000,0000,,and I don't think it's overly complex,
Dialogue: 0,0:17:16.08,0:17:21.88,Default,,0000,0000,0000,,you will be an oxidation state jock.
Dialogue: 0,0:17:21.89,0:17:23.75,Default,,0000,0000,0000,,So I think you're all set now.
Dialogue: 0,0:17:23.76,0:17:25.15,Default,,0000,0000,0000,,In the next video, we're going to start exploring
Dialogue: 0,0:17:25.16,0:17:28.15,Default,,0000,0000,0000,,oxidation reduction reactions.