Final answer:
The empirical formula of the compound with given masses of iron, phosphorus, and oxygen is calculated to be Fe3P1O4 after converting the masses to moles, dividing by the smallest mole number, and adjusting to the nearest whole number ratio.
Step-by-step explanation:
To determine the empirical formula of a compound, we need to convert the masses of iron, phosphorus, and oxygen to moles. The sample contains 6.81 g of iron, 1.26 g of phosphorus, and the rest is oxygen. First, we convert the mass of each element to moles using their atomic masses (Fe = 55.85 g/mol, P = 30.97 g/mol, and O = 16.00 g/mol):
- For iron (Fe): 6.81 g Fe × (1 mol Fe / 55.85 g Fe) = 0.122 mol Fe
- For phosphorus (P): 1.26 g P × (1 mol P / 30.97 g P) = 0.041 mol P
- For oxygen (O): (10.67 g – 6.81 g Fe – 1.26 g P) = 2.60 g O
2.60 g O × (1 mol O / 16.00 g O) = 0.163 mol O
Next, we divide the moles of each element by the smallest number of moles calculated, which in this case is for phosphorus (0.041 mol):
- 0.122 mol Fe / 0.041 mol = 2.98 ≈ 3
- 0.041 mol P / 0.041 mol = 1
- 0.163 mol O / 0.041 mol = 3.98 ≈ 4
We now have a ratio of Fe:P:O of approximately 3:1:4. Therefore, the empirical formula of the compound is Fe3P1O4.