Final answer:
The empirical formula of the iron oxide is FeO.
Step-by-step explanation:
The empirical formula of the iron oxide can be determined by finding the mole ratio of iron (Fe) to oxygen (O). To calculate the empirical formula, we need to convert the mass of each element to moles. From the given percentages, we can assume a 100g sample. The mass of iron is calculated as 77.7g and the mass of oxygen is calculated as 22.3g. Next, we calculate the moles of each element using their molar masses.
The molar mass of iron (Fe) is 55.845 g/mol and the molar mass of oxygen (O) is 15.999 g/mol. The moles of iron can be calculated by dividing the mass by the molar mass, giving 77.7g/55.845 g/mol = 1.39 mol. The moles of oxygen can be calculated similarly: 22.3g/15.999 g/mol = 1.39 mol. To find the simplest whole number ratio between the moles of iron and oxygen, we divide both by the smallest number of moles, which is 1.39 mol. This gives us a ratio of 1:1 for iron to oxygen. The empirical formula of the iron oxide is therefore FeO.