Question

How can empirical and molecular formulas be the same?

Answer 1

An empirical formula gives the ratio of the elements involved, reduced to the smallest numbers.

Explanation:

Example :
Let's say that the empirical formula is `CH_2O`. This means that carbon, hydrogen and oxygen are present in the ratio `1div2div1`.

So any compound with this ratio will do:
`C_6H_12O_6` (glucose) is one of them, among many, many others.

But there is also a compound `CH_2O`, formaldehyde (methanal), that is just that: `CH_2O`. So, in this case empirical=molecular.