Explanation: The density of a substance tells you the mass of exactly one unit of volume of said substance. In your case, aluminium is said to have a density of density Al = 2.70 g . cm − 3 This tells you that every 1 mL of aluminium has a mass of 2.70 g . All you have to do now is use the density of aluminium as a conversion factor to go from cubic centimenters of aluminium to grams 10.0 cm 3 ⋅ 2.70 g 1 cm 3 = 27.0 g −−−−− The answer is rounded to three sig figs.