Question

Which of the following represents the approximate osmotic pressure of a solution formed by dissolving 50.0 mg of aspirin, C₉H₈O₄, in 250 mL of water at 25°C?

A) 0.15 atm
B) 0.50 atm
C) 0.75 atm
D) 1.25 atm
E) 1.50 atm

Answer 1

The approximate osmotic pressure of the solution is 0.31 atm.

Step-by-step explanation:

The osmotic pressure of a solution can be calculated using the formula II = MRT, where II is the osmotic pressure, M is the molarity of the solution, R is the ideal gas constant, and T is the temperature in Kelvin. In this case, we need to convert the mass of aspirin to moles and then calculate the molarity of the solution. The molar mass of aspirin (C₉H₈O₄) is 180.16 g/mol. 50.0 mg is equivalent to 0.050 g. Using the formula M = moles of solute/volume of solution in liters, we can calculate the molarity of the solution: M = (0.050 g / 180.16 g/mol) / 0.250 L = 0.111 M. Finally, we can calculate the osmotic pressure using the formula II = MRT: II = (0.111 M) x (0.0821 L·atm/(mol·K)) x (25 + 273.15 K) = 0.308 atm, which is approximately equal to 0.31 atm.