BCC Chemistry The Molar Mass of Lysozyme Questions

Overview

1. How many grams of ethylene glycol (C2H6O2) must be added to 1.00 kg of water to produce a solution that freezes at -5.00o C?
2. 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 25o C. What is the molar mass of lysozyme?
3. Most fish need at least 4 ppm dissolved O2 in water for survival.
   1. What is this concentration in mol/L?
   2. What partial pressure of O2 above water is needed to obtain 4 ppm O2 in water at 10oC? (The Henry’s law constant for O2 at this temperature is 1.71 x 10-3mol/L-atm.)
4. The strength of alcoholic beverages like beer, wine, and spirits is typically expressed in units of alcohol by volume or abv. The abv is calculated by dividing the volume of ethanol (C2H5OH) by the total volume of solution. If the abv of a strong beer like a doppelbock is 8.0%, we can express the concentration in other units from the density of H2O and C2H5OH, which are 1.0 g/mL and 0.79 g/mL at 20o C, respectively. What is the concentration of this beer in
   1. mass percent (also known as alcohol by weight or abw),
   2. mole percent,
   3. molarity,
   4. molality?
5. Carbon disulfide (CS2) boils at 46.30o C and has a density of 1.261 g/mL.
   1. When 0.250 mol of a nonelectrolyte solute is dissolved in 400.0 mL of CS2, the solution boils at 47.46o C. What is the molal boiling-point-elevation constant for CS2?
   2. When 5.39 g of an unknown nonelectrolyte solute is dissolved in 50.0 mL of CS2, the solution boils at 47.08o C. What is the molar mass of the unknown solute?
6. A lithium salt used in lubricating grease has the formula LiCnH2n+1O2. The salt is soluble in water to the extent of 0.036 g per 100 g of water at 25o C. The osmotic pressure of this solution is found to be 57.1 torr. Assuming that molality and molarity in such a dilute solution are the same and that the lithium salt is completely dissociated in the solution, determine an appropriate value of n in the formula for the salt.
7. At ordinary body temperature (37o C), the solubility of N2 in water at ordinary atmospheric pressure (1.0 atm) is 0.015 g/L. Air is approximately 78 mol%N2.
   1. Calculate the number of moles of N2 dissolved per liter of blood, assuming blood is a simple aqueous solution.
   2. At a depth of 100 ft in water, the external pressure is 4.0 atm. What is the solubility of N2 from air in blood at this pressure?
   3. If a scuba diver suddenly surfaces from this depth, how many milliliters of N2 gas, in the form of tiny bubbles, are released into the bloodstream from each liter of blood?