The average osmotic pressure of blood is 7.70 atm at 25 ° C. What is the molar concentration of an aqueous glucose (C₆H₁₂O₆) solution that is isotonic (equal in concentration) with blood?

Question

Quizplus · Accepted Answer

Isotonic solutions have the same osmotic pressure. Thus, the molar concentration of glucose (which doesn't dissociate in water) in the isotonic solution with blood can be calculated using the van't Hoff equation:

Π = iMRT

where Π is the osmotic pressure, i is the van't Hoff factor (1 for glucose), M is the molarity, R is the gas constant, and T is the temperature in Kelvin. Rearranging the equation, we get:

M = Π / iRT

Plugging in the values (Π = 7.70 atm, i = 1, R = 0.08206 L·atm/mol·K, T = 298 K), we get:

M = 7.70 atm / (1 mol/L × 0.08206 L·atm/mol·K × 298 K) = 0.315 M

Therefore, the answer is choice C.

The Average Osmotic Pressure of Blood Is 7