00:01
For this problem, we're asked to find two empirical formulas and one molecular formula.
00:14
For our first problem, we're given 78 .9 % mercury and 26 .1 % chlorine.
00:30
There's a little poem we use that's called percent to mass, mass to mole, divide by small, multiply to a whole.
00:38
Percent to mass means simply changing your percent to mass.
00:42
It's that easy.
00:43
Mass to mole means dividing by your molar mass 200 .59 and 35 .45.
01:07
Okay, so my first one, i've got 78 .7 divided by 200 .59.
01:14
And that will equal 0 .3923 moles of hg.
01:22
26 .1 divided by 35 .45 is 0 .736 .6 .1.
01:25
Divided by 35 .45 is 0 .736.
01:29
Of h or of cl.
01:38
78 .7 divided by 200 .59 .69 or 26 .1.
01:49
Is that right? did i copy my numbers down right? 3 .9 .9.
01:59
There we go.
02:01
73 .9 divided, i saw they didn't add up to 100.
02:08
Whoops, let's try 78 .9 divided by 200 .59 .9.
02:20
And that's 0 .3933.
02:25
Okay, present to mass, mass to mold, divide by small.
02:53
I don't want this to be 1 .87.
02:57
Man, i just really copied this one down wrong.
03:03
I wonder if i was looking at the wrong thing.
03:08
This is 73 .9.
03:18
Okay, now i'm feeling better about life...