Answer:
P4Se3
Explanation:
Applying the Law of Conservation of Mass:
(133 mg total) - (45.8 mg P) = 87.2 mg Se
Dividing by the molar mass,
Phosphorus:-(45.8 mg P) / (30.97376 g P/mol) = 1.4786 mmol P
Selenium:-(87.2 mg Se) / (78.96 g Se/mol) = 1.1044 mmol Se
Divide by the smaller number of millimoles:
(1.4786 mmol P) / 1.1044 mmol = 1.339
(1.1044 mmol Se) / 1.1044 mmol = 1.000
multiply by 3, to get a whole number interger. then round to the nearest whole numbers to find the empirical formula.
Therefore the empirical formula is P4Se3
