# A compound with empirical formula CH was found by experiment to have a molar mass of approximately 91. What is the molecular formula of the compound?

So, $M F = n \cdot \left(E F\right)$, where $M F , E F$ are the molecular and empirical formulae respectively.
Thus, $91 \cdot g \cdot m o {l}^{-} 1 = n \times \left(12 + 1\right) \cdot g \cdot m o {l}^{-} 1$.
Or $n = \frac{91}{13}$; so $n$ $=$ $7$? Please report the molecular formula back here.