What is the empirical formula of this pigment?

Question

When C.I. Pigment Yellow 45 is analyzed, a 2.164g sample of this substance was found to contain 0.5259g of Fe and 0.7345g of Cr. The remainder was oxygen. Calculate the empirical formula of this pigment. What additional data is needed to calculate the molecular mass of this compound?

Answer 1

Forty Two ..YARRRRRHHHH no other data needed

Answer 2

the total mass is 2.164g.  if the only 3 elements are Fe, Cr, and O, the remaining O constitutes (2.164-.5259-.7345)=0.9036g O.  for the empirical formula, we compute the moles of each element: .5259gFe/55.845g:.7345gCr/51.9961g:.9036... => 0.009417molFe:0.01413molCr:0.05648molO.  if we divide through by the smallest number, we get 1:1.5:6. since we need whole numbers, the empirical ratios is 2:3:12.  to compute the molecular mass, we need the molecular formula, since the molecular mass could be any multiple of the "empirical formula mass".  hope this helps!

Answer 3

42