00:02
Hi there.
00:03
In this question, we are trying to determine the molecular formula for a compound that's composed of nitrogen and oxygen.
00:11
So that means it's going to have the formula n to the x, o to the y, and our task is to figure out what x and y are.
00:19
Well, let's assume we have just one mole of this.
00:22
The formula is going to be the same regardless how much we have, but let's just assume we have one mole of it.
00:28
Therefore, in that one mole, we need to figure out the number of moles of nitrogen and the number of moles of oxygen.
00:41
Because that will give us the subscripts.
00:44
If we know the moles of nitrogen and moles of oxygen, that will give us these subscripts.
00:50
And when we assume one mole, the mass of the compound that we have is going to be 92 .02 grams.
00:57
Because one mole multiplied times 92 .02 grams per mole simply gives us 92 .02 grams.
01:09
That's the mass of one mole of this.
01:13
Okay, so we're going to use all this information.
01:15
We know that the compound is 30 .45 % nitrogen by mass.
01:21
So i'm going to take 30 .45 % of this 92 .02 grams.
01:31
And what that gets us, is 28 .02.
01:40
So in one mole of this compound, there are 28 .02 grams of nitrogen.
01:46
I'm going to repeat this with oxygen's percent.
01:48
It's 69 .55 percent.
01:52
Again, the mass of this one mole is 92 .02 grams, giving us a mass of oxygen of 64 .00.
02:01
So in this compound, 28 .02 grams are nitrogen, and 64 .0...