Question

How would you determine the molecular formula of C4H9?

Answer 1

Just to retire this question ... are you sure that it is correctly posed...?

Explanation:

`C_4H_9` is not the formula of anything you could put in a bottle. It is the radical of some butane derivative, i.e. `C_4H_10`..

And so we have (possibly) `"tert-butyl radical"`...`(H_3C)_3C*`, the which is relatively long-lived...

On the other hand, you MIGHT have quoted an empirical formula of `C_4H_9`...to get the molecular formula, we need a measurement of the molecular mass...say we got a mass of `114.22*g*mol^-1`...this would correspond to a molecular formula of `C_8H_18`...and this is a saturated formula...