posted by w on .
The chemical analysis of aspirin indicates that the molecule is 60.00% carbon, 4.44% hydrogen, and 35.56% oxygen. What is the emperical formula for asprin?
Easy. Assume you have 100 g of the substance, so you have
60g C = 60/12 moles C= 5 mol C
4.44gH = 4.44/1= 4.44 mol H
35.56g O = 35.55/16 mol= 2.22 mol O
We want a whole number ratio, so divide all three of those moles by the lowest.
2.25 mol C
1 mol O
That is still not whole number, so we can get a whole number ratio by multiplying by 4
9 mol C
8 mol H
4 mol O
C9 H8 O4
Could it really be aspirin?