Question

Question #2c86e

Answer 1

The molecular formula will be `C_6H_6`; no prizes for guessing what this molecule is......

Explanation:

As with all these problems, it is useful to assume that there is a `100*g` mass of compound, and divide each elemental mass thru by the ATOMIC mass of each component.

And so..........

`"moles of carbon"-=(92.5*g)/(12.011*g*mol^-1)=7.70*mol`

`"moles of hydrogen"-=(7.50*g)/(1.00794*g*mol^-1)=7.50*mol`

And if we divide thru by the LOWEST molar quantity we gets.....and empirical formula of `CH`.

But the molecular formula is always a whole number of the empirical formula:

`"molecular formula"="empirical formula"xxn`

And so `78*g*mol^-1=nxx(12.011+1.00794)*g*mol^-1`; clearly, `n=6`, and the `"molecular formula"` is `C_6H_6`, which is what VERY common organic molecule?