# What is the chemical formula of C4H9 with a molar mass of 114.26 g/mol?

Nov 13, 2015

I believe you have quoted an empirical formula. Empirical formulae are distinct from molecular formula.

#### Explanation:

The empirical formula is the simplest whole number ratio that defines constituent atoms in a species. The molecular formula is always a multiple of the empirical formula; and the mulitple might be $1$.

So ${\left[E F\right]}_{n} = M F$.

We have to find the multiple $n$ for the empirical formula ${C}_{4} {H}_{9}$.

$\left(4 \times 12.011 + 9 \times 1.00794\right) g \cdot m o {l}^{-} 1 \times n = 114.26 \cdot g \cdot m o {l}^{-} 1$.

Here I used the atomic masses of carbon and hydrogen. It is pretty clear that the mulitple, $n$, $= 2$.

So molecular formula $= {\left[E F\right]}_{n} = 2 \times \left({C}_{4} {H}_{9}\right) = {C}_{8} {H}_{18}$. Do I win 5 pounds?