What is the empirical formula of a oxide of cobalt that contains a #1.216*g# mass of metal, and a #0.495*g# mass of oxygen?
We interrogate the molar quantities of metal and oxygen.....
We divide thru by the smallest molar quantity, that of the metal, to get a trial empirical formula of.....
But by specification, the empirical formula is the simplest whole number ratio defining constituent atoms in a species...and so....
This is not a good question inasmuch as
Assuming complete reaction of both, convert the masses into moles and normalize. I’ll use a singlet oxygen because we don’t know the ratio yet, even though the actual gas would be diatomic.