© Department of Physics, University of Guelph
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1. With C the concentration of a solute in water, measured in grams (of solute) per cubic metre (of solvent) and with M the molar mass (grams per mole) of solute:
(a) Show that C/M is given by moles (of solute)/m3 (of solvent).
(b) Under what condition will C/M also be given by moles (of solute)/m3 (of solution)?
(c) Under what condition are the molarity and molality of the solution in part (b) likely to be the same?
2. A dilute solution of sucrose is made up with concentration C. If the volume of the solution is increased by 33% by the addition of pure water, the concentration will now be:
(a) 4/3 C
(b) 2/3 C
(c) 3/2 C
(d) 3/4 C
(e) 1/3 C
3. An experimenter finds that a solution containing 15.0 mg cm3 of a pure protein has an osmotic pressure of 100 Pa. Assuming ideal behaviour, what would be the molar mass of the protein? (T = 300 K)
4. Suppose some red blood cells such as those described in the text are placed in a large volume of a solution containing 0.30 molar glycerol plus 0.15 molar NaCl. What will happen to the cell? Remember the NaCl will not cross but the glycerol will.
5. Some red blood cells (0.30 Os) are placed in a NaCl solution of concentration 0.27 Os.
(a) Do they swell or shrink?
(b) By what percentage does each cell volume
change?