posted by jaz on .
Determining a Molecular Formula from an Empirical Formula
1. A compund has an experimental molar mass of 78g/mol. Its empirical formula is CH. What is its molecular formula?
The idea here is to see how many CH groups you have or put another way (CH)x where you want to determine x.
So if x is 1, what would the molar mass be? It would be 12 for C + 1 for H = 13 for the CH. If x = 2, then the molar mass would be 26. If x = 3, the molar mass would be 3 x 13 = 39. So what time 13 = 78 (or close to it).
13 times 6 =78
but the relative atomic mass of C=12 and H=1
therefore the molecular mass would be
13n = 78 g/mol
the molecular formula is C6H6 .