Here's how to calculate the moles of formula units in 5.67 g of iron sulfate (FeSO₄):

1. Determine the molar mass of iron sulfate:

* Fe: 55.845 g/mol

* S: 32.065 g/mol

* O: 15.999 g/mol (x4)

* Total molar mass: 55.845 + 32.065 + (15.999 x 4) = 151.908 g/mol

2. Convert grams to moles using the molar mass:

* Moles = mass / molar mass

* Moles = 5.67 g / 151.908 g/mol

* Moles ≈ 0.0373 moles

Therefore, there are approximately 0.0373 moles of formula units in 5.67 g of iron sulfate.