Answer:
436.55841 grams.
Step-by-step explanation:
The molecular formula for Iron(III) Iodide is FeI3. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Iron(III) Iodide, or 436.55841 grams.
You use the 1 / 436.55841 conversion rate. This is different for each element, according to the stoichiometry tables. Iron(II) oxide would be 2/3 of the 1/436.55841 conversion rate, that is, multiplying the fraction to denominator.