How many acetone molecules are in a bottle of acetone with a volume of 395 mL ? (density of acetone = 0.788 g/cm3).?

Volume of CH₃COCH₃ = 395 mL = 395 cm³

Density of CH₃COCH₃ = 0.788 g/cm³
Mass of CH₃COCH₃ = (0.788 g/cm³) × (395 cm³) = 311.3 g

Molar mass of CH₃COCH₃ = 12.01×3 + 1.01×6 + 16.00 = 58.09 g/mol
Number of moles of CH₃COCH₃ = (311.3 g) / (58.09 g/mol) = 5.359 mol

1 mole of CH₃COCH₃ has 6.022 × 10²³ molecules.
Number of CH₃COCH₃ molecules = (6.022 × 10²³ /mol) × (5.359 mol) = 3.23 × 10²⁴