Question

What is the empirical formula of a compound composed of 33.9 g potassium (K) and 6.94 g oxygen

Answer 1

convert the mass into mols using molar mass. Then figure out the ratio of the mol between potassium and oxygen

Answer 2

33.9 g potassium is roughly 0.86722 mol K, and for oxygen it's roughly 0.43375. Divide the first by the second, you get 2:1 ratio. That's your empirical formula, K2O