The osmotic pressure of a solution that contains 6.0 g of NaCl per 100.0 g of solution that has a density of 1.02 g/mL at a temperature of 25˚C is _____ atm. (Given R = 0.0821 L.atm/mol.K)
A) 32
B) 51
C) 45
D) 25
E) 5

Question

Quizplus · Accepted Answer

To find the osmotic pressure, use the formula π = iMRT. First, calculate the molarity (M) of the NaCl solution. The mass of the solution is 100 g, and with a density of 1.02 g/mL, the volume is 98.04 mL or 0.09804 L. The molar mass of NaCl is 58.44 g/mol, so 6.0 g is 0.1027 mol. The molarity is 0.1027 mol / 0.09804 L = 1.048 M. NaCl dissociates into 2 ions (i = 2). At 25˚C (298 K), π = 2 * 1.048 * 0.0821 * 298 = 51 atm.

The Osmotic Pressure of a Solution That Contains 6