H2O, O2, Al, Fe (iron), Ag (silver), and Au (gold). I dont know the chemical makeup of steel though. Density is equivalent to mass over volume (d=m/v) so im guessing that all these you just listed are in the same quantity. I got these answers by the molar mass of these compounds/elements. Higher molar mass= higher density
List the following substance in order from lowest density to highest density iron, gold, steel, water , air , silver and aluminum.