The osmotic pressure of an aqueous solution of urea (molar mass = 60 g mol ⁻¹ ) is 0.492 atm at 300 K . Assuming the density of the solution to be 1.0 g mL ⁻¹ and using R = 0.082 L atm K ⁻¹ mol ⁻¹ , what is the concentration of urea in the solution in parts per million (ppm)?

Step-by-step solution

Using the formula for osmotic pressure = CRT , the molarity C of the solution is calculated as follows: C = RT = 0.492 0.082 300 = 0.492 24.6 = 0.02 mol L ⁻¹ Mass of urea in 1 L of solution = 0.02 mol 60 g mol ⁻¹ = 1.2 g Given the density of the solution is 1.0 g mL ⁻¹ , the mass of 1 L ( 1000 mL ) of solution is 1000 g . Concentration in ppm = Mass of solute Mass of solution 10^6 Concentration in ppm = 1.2 1000 10^6 = 1200 Answer: 1200