Volume of one molecule = 34πr3 = 34 π (1.54×10−8)3cm3 = 1.53 × 10−23cm3 Volume of molecules in 1.65 g Ar = 401.65 × N0 × 1.53 × 10−23 = 0.380 cm3 Volume of solid containing 1.65 gAr = 1 cm3 ∴ Empty space = 1-0.380 = 0.620 ∴ Percent of empty space = 62%