Question

If the `"empirical formula"` is `CH`, and the molecular mass is `26*g*mol^-1`, what is the `"molecular formula"`?

Answer 1

The molecular formula is always a whole number of the empirical formula...........

Explanation:

............and of course the multiple may be one.

And thus `"molecular formula"="n"xx"empirical formula"`

And so the given molecular mass is `26*g*mol^-1`.

And so `26*g*mol^-1=nxx(12.0*g+xx1*g)`

Clearly, `n=2`, and the molecular formula is `C_2H_2`, which is good because of course we know that `"acetylene"=H-C-=C-H`, i.e. two degrees of unsaturation.