Question

How do you determine the empirical formula of a compound that has the following composition: 92.3 percent C and 7.7 percent H?

Answer 1

As with all these problems, we assume that there are `100*g` of unknown compound........to give an empirical formula of `CH`.

Explanation:

And then we work out the molar composition.

Thus `"Moles of carbon"` `=` `(92.3*g)/(12.011*g*mol^-1)=7.68*mol`.

And `"Moles of hydrogen"` `=` `(7.7*g)/(1.00794*g*mol^-1)=7.64*mol`.

Clearly, there is `1:1` molar equivalence with respect to `C:H`.

The molecular formula is a multiple of the empirical formula, but we have no handle on that here.