Question

what is the molecular formula of a compound with an empiricla formula of ch and a molecular mass of 78

Answer 1

Answer:

C6H6

Explanation:

We can obtain the molecular formula from the empirical formula.

What we need do here is:

(CH)n = 78

The n shows the multiples of both element present in the actual compound. It can be seen that carbon and hydrogen have the same element ratio here. We then use the atomic masses of both elements to get the value of n. The atomic mass of carbon is 12 a.m.u while the atomic mass of hydrogen is 1 a.m.u

(1 + 12)n = 78

13n = 78

n = 78/13 = 6

The molecular formula is

(CH)n = (CH)6 = C6H6