Answer:
Fe₃PO₄
Explanation:
They have given the total mass of the compound, the mass of iron and the mass of phosphorus. So we can find the mass of oxygen.
Mass of oxygen = 12.17 - (7.77 + 1.44) = 2.96g
So we can now find the empirical formula.
Element - mass - Mr - Mass÷Mr - Ratio - Simplest Ratio
Fe - 7.77g - 55.8 - [7.77÷55.8] - [0.14÷0.05] - 2.8 = 3
P - 1.44g - 31 - [1.44÷31] - [0.05÷0.05] - 1
O - 2.96g - 16 - [2.96÷16] - [0.19÷0.05] - 3.8 = 4
[The simplest ratio was obtained by dividing the answer of mass÷mr with the smallest value. Phosphorus had the smallest value of mass÷mr=0.05, so all other answer were divided by 0.05]
Emperical formula = Fe₃PO₄