What is the osmotic pressure generated at 25°C by a solution of 1.26 g of sucrose, C₁₂H₂₂O₁₁, in 250 cm³ of water?

Question

Quizplus · Accepted Answer

First, calculate the molarity of the sucrose solution:

1.26 g sucrose / 342.3 g/mol sucrose = 0.00369 mol sucrose
250 cm³ water = 0.25 L water

Molarity = moles of solute / liters of solution

Molarity = 0.00369 mol / 0.25 L = 0.01476 M

Then, use the Van't Hoff equation to calculate the osmotic pressure:

π = iMRT

where:
π = osmotic pressure
i = van't Hoff factor (1 for sucrose)
M = molarity (0.01476 M)
R = gas constant (0.08206 L•atm/mol•K)
T = temperature in Kelvin (25°C + 273.15 = 298.15 K)

π = (1)(0.01476 M)(0.08206 L•atm/mol•K)(298.15 K)
π = 0.0364 atm
π = 36.4 kPa

Therefore, the answer is B.

What Is the Osmotic Pressure Generated at 25°C by a Solution