What is the osmotic pressure (in atm) of a solution formed by dissolving 65.9 mg of aspirin (C9H8O4, 180.16g/mol) in enough water to make 250 mL of solution at 25 °C?

Question

Enter your value with three significant figures .

Answer 1

P = icRT

n = 65.9E-3 g / 180.16 g / mol = 3.66E-4 mol

c = n / V = 3.66E-4 mol / 0.250 L = 1.46E-3 mol / L

R = 0.082057 L * atm / (mol * K)

T = 298 K

i = 1aspirin - non electrolyte (very weak acid)

P = 1 * 1.46E-3 mol / L * 0.082057 L * atm / (mol * K) * 298 K = 0.0357 atm