empirical formula of the compound

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1) A compound of iron and oxygen is found to have a mass of 6.13 grams. If the mass of iron is determined to be 4.29grams, what is the empirical formula of the compound?(6.13-4.29 = 1.84 g oxygen)
Right now you are comparing the masses of two different elements, which cannot be done properly (1 pound of gold is much less than 1 pound of feathers....)

We need to compare them on a mole by mole basis, so we figure out the molar masses for each.

MMFe = 56 g/mol
MMO = 16 g/mol
4.29 g /56 = 0.077 moles of iron
1.84 g/16 = 0.115 moles of oxygen

These need to be in whole number form, so we will divide by the smallest number...

0.077/0.077 = 1
0.115/0/077 = 1.5

Still not good enough, we need whole ...