Practice question
Question
What is the molar mass of a solute if 6 g of it in 300 mL of solution produces an osmotic pressure of 0.821 atm at 27°C? ( R = 0.0821 L atm mol⁻¹ K⁻¹ )
Explanation
Pi = (w/M V) RT . 0.821 = (6/M × 0.3) × 0.0821 × 300 . M = (6 × 0.0821 × 300/0.821 × 0.3) ≈ 60 g/mol .