Chem question please help

Question

a 0.400g sample of white powder contains 0.141g of potassium, 0.115g of sulfur and 0.144g of oxygen. What is the empirical formula for this compound?

Answer 1

Calculate the moles of each element that is present.

moles potassium (K) = 0.141 g x 1 mol/39.098 g = 0.003606 moles K

moles sulfur (S) = 0.115 g x 1 mol/32.065 g = 0.003586 moles S

moles oxygen (O) = 0.144 g x 1 mol/16 g = 0.009 moles O

Divide by the smallest number of moles in order to get whole numbers

K = 0.003606/0.003586 = 1.00

S = 0.003586/0.003586 = 1.00

O = 0.009/0.003586 = 2.51

Since 2.51 is not a whole number, you can get all whole numbers by multiply all by 2 and you end up with 

K₂S₂O₅ = empirical formula