Answer:
1
Explanation:
1.04/MM = 1.04/39.09 = 0.0266 potassium moles
0.7/MM = 0.7/52 = 0.0133 chromium moles
0.86/MM =0.86/16 = 0.05375 oxygen moles
divide all the moles number by the lowest
0.0266/0.0133=2
0.0133/0.0133=1
0.05375/0.133=4
so the empirical formula is K2CrO4