Henry’s law is important in environmental chemistry,where it predicts the distribution of pollutants betweenwater and the atmosphere. Benzene (C6H6) emitted inwastewater streams, for example, can pass into the air,where it is degraded by processes induced by light fromthe sun. The Henry’s law constant for benzene in water at25°C is 301 atm. Calculate the partial pressure of benzenevapor in equilibrium with a solution of 2.0 g of benzeneper 1000 L of water. How many benzene molecules arepresent in each cubic centimeter?

The osmotic pressure of a solution containing 7.0 g of insulin per liter is 23 torr at 25 C. What is the molar mass of insulin?

6-111 As noted in Section 6-8C, the amount of external pressure that must be applied to a more concentrated solution to stop the passage of solvent molecules across a semipermeable membrane is known as the osmotic pressure The osmotic pressure obeys a law similar in form to the ideal gas law (discussed in Section 5-4), where Substituting for pressure and solving for osmotic pressures gives the following equation: RT MRT, where M is the concentration or molarity of the solution. (a) Determine the osmotic pressure at 25°C of a 0.0020 M sucrose (C12H22O11) solution. (b) Seawater contains 3.4 g of salts for every liter of solution. Assuming the solute consists entirely of NaCl (and complete dissociation of the NaCI salt), calculate the osmotic pressure of seawater at 25°C. (c) The average osmotic pressure of blood is 7.7 atm at 25°C. What concentration of glucose (C6H12O6) will be isotonic with blood? (d) Lysozyme is an enzyme that breaks bacterial cell walls. A solution containing 0.150 g of this enzyme in 210. mL of solution has an osmotic pressure of 0.953 torr at 25°C. What is the molar mass of lysozyme? (e) The osmotic pressure of an aqueous solution of a certain protein was measured in order to determine the protein's molar mass. The solution contained 3.50 mg of protein dissolved in sufficient water to form 5.00 mL of solution. The osmotic pressure of the solution at 25°C was found to be 1.54 torr. Calculate the molar mass of the protein.

The freezing point of a 0.11 m solution of HNO2 is -0.20C. (a) What is i for the solution? (b) Is the solution made (i) of HNO2 molecules only? (ii) of H+ and NO2- only? (iii) of more HNO2 molecules than H+ ions? (iv) primarily of H+ and NO2- ions with some HNO2 molecules?