00:01
In this video, we want to balance this redox reaction under acidic conditions.
00:07
All right.
00:08
So one of the equations is going to involve magnesium because magnesium is in a compound, and then it becomes an element.
00:19
So it has to change oxidation numbers just by inspection alone, because when it goes from charges to zero charge.
00:29
So specifically, when it's in the ionic state, it's a plus two.
00:33
And then in the elemental state, it's a zero.
00:34
So we can write our half reaction, and the oxidation number goes down.
00:38
So this is a reduction.
00:40
So we could say magnesium 2 plus becomes magnesium, and we need two electrons on this side to balance out the charge.
00:51
Nitrate, in this case, is a spectator ion, because it shows up on both sides of the equation on change.
00:57
So we can leave it like so.
00:58
And then for the oxidation by default, so we know nitrate doesn't matter.
01:03
So let's look at hydrogen.
01:05
Hydrogen is an element, and then it goes to h plus.
01:07
So it goes from zero to plus one, meaning oxidation number increases.
01:14
So we have h2 becomes 2h plus...