Question

How many moles of Fe are present in 30g of rust

Answer 1

This depends upon what you consider the formula for rust. That varies. If you consider it as Fe2O3 (but that isn't exact) then moles = grams/molar mass = 30/aapproximately160 = 0.188 moles rust and there are 2 mols Fe for each mole of Fe2O3 so that would be 2 x 0.188 = ?