Macmillan Learning o What is the boiling point of a 11.75 m aqueous solution of the nonelectrolyte ethylene glycol at sea level? The boiling point constant, Kы, for water is 0.512 °C/m. Assume pure water boils at 100.00 °C at sea level. Tb = °C

Consider three test tubes. Tube A has pure water. Tube B has an aqueous 1.0 m solution of ethanol, C2H5OH. Tube C has an aqueous 1.0 m solution of NaCl. Which of the following statements are true? (Assume that for these solutions 1.0m=1.0M.) (a) The vapor pressure of the solvent over tube A is greater than the solvent pressure over tube B. (b) The freezing point of the solution in tube B is higher than the freezing point of the solution in tube A. (c) The freezing point of the solution in tube B is higher than the freezing point of the solution in tube C. (d) The boiling point of the solution in tube B is higher than the boiling point of the solution in tube C. (e) The osmotic pressure of the solution in tube B is greater than the osmotic pressure of the solution in tube C.

You have read that adding a solute to a solvent can both increase the boiling point and decrease the freezing point. A friend of yours explains it to you like this: The solute and solvent can be like salt in water. The salt gets in the way of freezing in that it blocks the water molecules from joining together. The salt acts like a strong bond holding the water molecules together so that it is harder to boil. What do you say to your friend?

Arrange 0.10 m aqueous solutions of the following solutes in order of decreasing freezing point and boiling point. (a) Al(ClO3)3(b) CH3OH (c) (NH4)2Cr2O7 (d) MgSO4

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.

What is the freezing point and normal boiling point of a solution made by adding 39 mL of acetone, C3H6O, to 225 mL of water? The densities of acetone and water are 0.790 g/cm3 and 1.00 g/cm3, respectively.

1. Vapor pressure: Arrange the following aqueous solutions in order of increasing vapor pressure at 25°C: 0.35 m C2H4(OH)2 (ethylene glycol, nonvolatile solute); 0.50 m sugar; 0.20 m KBr; and 0.20 m Na2SO4. C2H4(OH)2 < sugar < KBr < Na2SO4 Na2SO4 < sugar < KBr < C2H4(OH)2 sugar < C2H4(OH)2 < KBr < Na2SO4 KBr < sugar < Na2SO4 < C2H4(OH)2

What would be the freezing point of a solution formed by adding 1.0 mole of glucose (a molecular compound) to the following amounts of water? a. 250 g (0.25 kg) b. 500 g (0.500 kg) c. 1000 g (1.000 kg) d. 2000 g (2.000 kg)

The vapor pressure of methanol, CH3OH, is 94 torr at 20 C. The vapor pressure of ethanol, C2H5OH, is 44 torr at the same temperature. (a) Calculate the mole fraction of methanol and of ethanol in a solution of 50.0 g of methanol and 50.0 g of ethanol. (b) Ethanol and methanol form a solution that behaves like an ideal solution. Calculate the vapor pressure of methanol and of ethanol above the solution at 20 C.

Consider two solutions, A and B, separated by an osmotic semipermeable membrane that allows only water to pass through, as shown in the diagram in Problem 8-113. Based on each of the following identities for solutions A and B, indicate whether the liquid level in compartment A, with time, will increase, decrease, or not change. a. A = 1.0 M glucose solution and B = 2.0 M glucose solution b. A = 5.0%(m/v) NaCl solution and B = 4.0%(m/v) NaCl solution c. A = 2.0 M Na2SO4 solution and B = 3.0 M KNO3 solution d. A = 2.0 M glucose solution and B = 1.0 M NaCl solution