1.Pepsin is the principal digestive enzyme of gastric juice. A 1.85 g sample of pepsin is dissolved in enough water to make 4.50 mL of solution. The osmotic pressure of the solution is found to be 0.292 atm at 25C. What is the molar mass of pepsin?

1a.A 0.5957 g sample of impure Ca(OH)2 is dissolved in 50.00 mL of water. 20.00 mL of the resulting solution is then titrated with 0.1769 M HCl. What is the percent purity of the Ca(OH)2 if the titration requires 22.18 mL of acid?