00:06
We are told that 15 milliliters of hydrogen bromide gas diffuses in one minute.
00:26
I'm using a different stylus, so i'm struggling a little bit.
00:41
And we're told that at the same apparatus, same conditions, 20 .3 milliliters of unknown, unk, unknown gas diffuses in one minute.
01:08
Find the unknown gas is a hydrocarbon, which means it contains only h and c atoms.
01:40
Find the molecular formula.
01:52
Okay, so we are going to set up a simple rate here, whoopsie, and our rate is going to be the rate of hbr over the rate of our unknown will equal the square root of the molar mass of the unknown over the molar mass of hbr.
02:32
Let's see here.
02:33
So i'm going to set up my rate as 15 over 1 .0 in one minute.
02:52
That's my rate divided by 20 .3 milliliters in one minute, which will equal the square root of, of x over 80 .912.
03:39
Let me get my calculator.
03:42
So i'm gonna square everything, so i'm gonna take 15 divided by 20 .3, enter, x squared enter, times 80 .912 enter.
03:57
And i get 44 .2, grams per mole.
04:15
And then i'm just going to try trial and error here...