Question

A compound, X contains 92.31 % C and 7.69 % H.

RMM of X is 78. Determine the molecular formula.​

Answer 1

C6H6

Step-by-step explanation:

We divide each percentage by the relative atomic mass of the element:

Carbon: 92.31 / 12.011 = 7.68

Hydrogen: 7.69 / 1.008 = 7.63

So the ratio of carbon to hydrogen is 1:1.

Empirical formula is CH - which has a MM of 13.019

The RMM is 78 so the molecular formula = 78/13.019 = 6 * CH

So it is C6H6 (Benzene).

Answer 2

C6H6

Step-by-step explanation:

Just use the table method to find the ratio of C to H and then compare the RMM with that of the empirical formula.