The formula is easy:
Gram formula mass
----------------------------
Emprical Formula
So if we plug in our own numbers,
114.0
--------
57.116
We get an answer of 1.99, which rounds to 2.
Then, we distribute based off of our empirical formula.
2(C4H9) becomes C8H18.
Our molecular formula is C8H18.
Hope I could help!
