Question

A compound with the empirical formula CH2 has a molar mass of 28 g/mol. What is the molecular formula for this compound?

Answer 1

The molecular formula is `"C"_2"H"_4"`.

Explanation:

Determine the empirical formula mass.

`"CH"_2":` `(1xx12"g/mol")+(2xx1"g/mol")="14 g/mol"`

Divide the molecular mass by the empirical formula mass.

`(28cancel"g/mol")/(14cancel"g/mol")=2`

Multiply the subscripts in the empirical formula times `2`.

The molecular formula is `"C"_2"H"_4"`.