A student found that 1.19 g of chromium (#Cr#) formed 1.74 g f chromium oxide. The molar mass of #Cr# is 52.00 g/mol. What is the empirical formula of chromium oxide?
As with all these problems, we calculate the molar quantities of each substituent, and normalize them according to the masses of the atomic constituents:
And we divide thru by the SMALLEST molar quantity, that of chromium, to give:
But by definition, the empirical formula is the smallest WHOLE number ratio that defines constituent atoms in a species. To get a whole number ratio, clearly we mulitply the empirical ratio by
How did I know there were