00:01
Okay, so for this question, they want us to find the molecular formula of crude oil.
00:05
And they say that crude oil is 97 .1 % carbon and 6 .29 % hydrogen.
00:12
And the molar mass is 128 grams.
00:14
So when we try to find a molecular formula with the empirical formula, you can think of it this way.
00:20
So 93 .71 % of the crude oil belongs to carbon and 6 .29 % of it belongs to hydrogen.
00:28
So out of 100 grams of crude oil, we should have 93 .71 grams of carbon and 6 .29 grams of hydrogen, right? so now we can convert, since we have grams, we can convert these into moles.
00:46
So 93 .71 divided by 12 grams because one mole of carbon is 12 grams, we should get 7 .81.
00:58
1 and now we do 6 .29 grams of hydrogen divide by 1 grams because a gram of 1 mole of hydrogen is 1 gram and we get 6 .29 so now what we do is we divide both of these modes by the lowest number the lowest moles which is 6 .29 right so we divide this by 6 .29 and we divide this by 6 .29 we should get 1 for hydrogen and for carbon we get 1 .5 0 .25, right, but we can't have a 0 .25.
01:35
We can't have like carbon 1 .25 and hydrogen 1 .25, right? so in order to fix this, we multiply both of these numbers by 4, right? we multiply 1 .25 by 4.
01:47
We get about 5.
01:49
And then we multiply 1 by 4.
01:51
We get 4...