Question

at 20C a cell with a pressure potential of 3 bars is in equilibrium with the surrounding .4M solution of sucrose in an open beaker. what is the molar concentration of sucrose in the cell?

Answer 1

 The solute potential $\Psi_S = -iCRT$ , where i is the ionization constant, C is the molar concentration, R is the pressure constant (R = 0.0831 liter bars/mole K).

i = 1 (for sucrose)

$\Psi_{S(surround.)} = -(1)\times (0.4)\times (0.0831)\times (273+20)$

$\Psi_{S(surround.)} = -9.74$

$\Psi_{S(surround.)} = \Psi_P + \Psi_S$

$-9.74 = 3 + \Psi_S$

$\Psi_S = -12.74$

$\Psi_S = iCRT$

$-12.74 = -(1)\times C\times (0.0831)\times (273+20)$

$-12.74 = -24.34C$

$C = 0.52\; M$

Answer: 0.52 M