Question

A compound has the empirical formula CH and a molar mass of 78.11 g/mol . Find its molecular formula.

Answer 1

C - 12.01 g/mol

H - 1.008 g/mol

CH - 13.018g/mol

molecular formula = n×(empirical formula)

78.11 g/mol = n ×( 12.01 + 1.008) g/mol

∴ n = 5.99

≈ 6

then
`C_(6) H_(6)`

Explanation: First find the molar mass of the empirical formula CH.

use the formula that says: Molecular formula = n × empirical formula

therefore you divide the molar mass of the compound by molar mass of the empirical formula.

the empirical is the 6th and then multiply that 6 with the subscripts of CH.