Compute the osmotic pressure developed across the membrane shown in Fig. 2.36 if the saline water has a weight fraction of CaCl, of (1) 0.10, (2) 0.30, or (3) 0.44 (assume T=70F). Answer: 1,0003; 8,500; and 22,500 psi. 76 VAPOR WATER MOLECULE SALT MOLECULE WA ER SALINE SOLUTION 1. ME MBRANE Fig. 2.36-Osmosis of water through a semipermeable membrane.