session 9 practice problems

a water-miscible solvent used in a water based solution to enhance the solubility of a drug with poor aqueous solubility

cosolvent

an amount of a compound that contains 6.022 × 10^23 molecules of that compound and has a mass equal to its molecular weight

mole

the number of moles of solute in one liter of solution

molarity

the number of moles of solute in a solution divided by the total moles of the solution

mole fraction

the number of moles (n) of solute in one kilogram of solvent

molality

properties that depend upon the concentration of solute molecules or ions, but not upon the chemical identity of the solute

colligative properties

corrects for the fact that ionic compounds (electrolytes) dissociate into multiple solute particles (ions) upon dissolution

van’t hoff factor

the diffusion of a fluid through a semipermeable membrane to establish equal concentration

osmosis

a solution with the same osmolarity as a specific body fluid is said to be this with respect to that specific body fluid

isotonic

swelling and rupture of red blood cells that can result from water moving from the solution into the blood cells

hemolysis

a process whereby red blood cells shrivel and die due to water moving from inside the cells out into solution

crenation

If red blood cells are suspended in a solution of aqueous sodium chloride with an osmolarity well below normal plasma osmolarity, which one of the following is the most likely result?

 

hemolysis

 

crenation

 

no effect

hemolysis

For non-electrolytes, the dissociation or Van’t Hoff factor (i) is equal to one.

 

True

 

False

True

A preparation of ketoprofen calls for a 5.0 mg/mL solution in a mixture of water and dimethylsulfoxide (DMSO). The solubility of ketoprofen in water is 0.051 mg/mL while its solubility in DMSO is 30 mg/mL. Calculate the volume fraction of DMSO required for this preparation? Use the formula below.

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Addition of a solute to a solvent ____ the boiling point of the solution relative to the pure solvent

raises

The vapor pressure of a solution is directly proportional to the _____ of the _____

mole fraction; solvent

Addition of a solute to a solvent ______ the vapor pressure of the solvent

lowers

The effect of a solute on the boiling point of the solution is directly proportional to the _____ of the _____ .

molality; solute

Addition of a solute to a solvent _____ the freezing point of the solution relative to the pure solvent

lowers

The effect of a solute on the freezing point of the solution is directly proportional to the ______ of the ____

molality; solute

Potassium chloride is a strong electrolyte. Assume it completely disassociates according to the equation below.

Urea is a non-electrolyte. Solution A is prepared by dissolving 1.5 moles of potassium chloride in enough water to make one liter of solution. Solution B is prepared by dissolving 2.0 moles of urea in enough water to make one liter of solution.

Which one of the following statements is TRUE?

 

Solution A is hyperosmotic with respect to solution B.

 

Solution A and B are isosmotic.

 

Solution B is hyperosmotic with respect to solution A.

 

None of the other statements are true.

Solution A is hyperosmotic with respect to solution B.

Both calcium chloride and calcium carbonate are strong electrolytes. Assume both completely disassociate according to the equations below.

Solution A is prepared by dissolving one mole of calcium chloride in one kilogram of water. Solution B is prepared by dissolving one mole of calcium carbonate in one kilogram of water. Which solution will have the lower freezing point?

 

Solution B

 

The freezing point will be the same for both solutions.

 

Solution A

Solution A

Which colligative property lowers in proportion to the molality of the solute?

 

boiling point

 

osmotic pressure

 

vapor pressure

 

freezing point

freezing point

Calcium chloride is a strong electrolyte. Assume it completely disassociates according to the equation below.

Dextrose is a non-electrolyte. Solution A is prepared by dissolving 1.0 mole of calcium chloride in one kilogram of water. Solution B is prepared by dissolving 3.0 moles of dextrose in one kilogram of water. Which solution will have the higher boiling point? 

 

Solution B

 

The boiling point will be the same for both solutions.

 

Solution A

The boiling point will be the same for both solutions

If red blood cells are suspended in a solution of aqueous sodium chloride with an osmolarity well above normal plasma osmolarity, which one of the following is the most likely result?

 

no effect

 

hemolysis

 

crenation

crenation

Identify ALL of the FALSE statements. You may select more than one answer.

 

The vapor pressure of a solution is directly proportional to the molarity of the solute.

 

The diffusion of a fluid through a semipermeable membrane to establish equal concentration is known as osmosis.

 

Mole fraction is the number of moles (n) of solute in one liter of solution.

 

A co-solvent is a a water-miscible solvent used in a water based solution to enhance the solubility of a drug with poor aqueous solubility.

 

The Van't Hoff Factor corrects for the fact that ionic compounds (electrolytes) dissociate into multiple solute particles (ions) upon dissolution.

The vapor pressure of a solution is directly proportional to the molarity of the solute

Mole fraction is the number of moles (n) of solute in one liter of solution.

Both calcium chloride and calcium carbonate are strong electrolytes. Assume both completely disassociate according to the equations below.

Solution A is prepared by dissolving 2.0 moles of calcium chloride in one kilogram of water. Solution B is prepared by dissolving 3.0 moles of calcium carbonate in one kilogram of water. Which solution will have the lower freezing point?

 

Solution A

 

The freezing point will be the same for both solutions.

 

Solution B

The freezing point will be the same for both solutions.

A preparation of griseofulvin calls for a 25 mg/mL solution in a mixture of water and N-methyl pyrrolidone (NMP). The solubility of griseofulvin in water is 8.64 mg/mL while its solubility in NMP is 100 mg/mL. Calculate the volume fraction of NMP required for this preparation? Use the formula below.

Enter your answer with two significant figures in the following format: "0.xx" 

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