CHEM 212 ACS EXAM QUESTIONS15
Colligative Properties
***Non-volatile non-electrolyte Solute - ANSWERS-Solute particles cannot enter the gas phase:
vapor pressure lowing and boiling point elevation
-Solute particles cannot enter the solid phase:
freezing point depression
-Solute particles cannot cross a semipermeable
membrane: osmotic pressure
Volatile Non-electrolyte Solutions - ANSWERS-For a volatile nonelectrolyte, the vapor of the
solution contains both solute and solvent.
-The presence of each volatile component lowers the vapor pressure of the other, since each
one lowers
the mole fraction of the other.
-For such a solution, the vapor will have a higher mole fraction of the more volatile component.
***The vapor has a different composition than the solution.
Strong Electrolyte Solutions - ANSWERSA strong electrolyte dissociates completely to form ions.
Each mole of solute gives more than 1 mol of dissolved particles
van't Hoff factor - ANSWERStakes into account the
dissociation of a strong electrolyte to predict the
effect on the solution.
Nonideal Behavior of Strong Electrolyte
, Solutions - ANSWERSIons in solution may remain
clustered near ions of
opposite charge, creating an
ionic atmosphere.
• The ions do not act
independently, and the
effective concentration of
dissolved particles is less
than expected.
Factors That Influence Reaction Rate - ANSWERSParticles must collide in order to react.
• (1) The higher the concentration of reactants, the
greater the reaction rate.
- A higher concentration of reactant particles allows a greater
number of collisions. (high collision frequency)
The physical state of the reactants influences
reaction rate. - ANSWERSSubstances must mix in order for particles to collide.
- Contact occurs only at the interface between the phase, so
vigorous stirring or even grinding may be needed.
- The more finely divide a solid or liquid reactant, and the
faster the reaction occurs.
Concentration of reactants-Why? - ANSWERSParticles must collide in order to react.
- A higher concentration of reactant particles allows a greater
number of collisions. (higher collision frequency, the greater
Colligative Properties
***Non-volatile non-electrolyte Solute - ANSWERS-Solute particles cannot enter the gas phase:
vapor pressure lowing and boiling point elevation
-Solute particles cannot enter the solid phase:
freezing point depression
-Solute particles cannot cross a semipermeable
membrane: osmotic pressure
Volatile Non-electrolyte Solutions - ANSWERS-For a volatile nonelectrolyte, the vapor of the
solution contains both solute and solvent.
-The presence of each volatile component lowers the vapor pressure of the other, since each
one lowers
the mole fraction of the other.
-For such a solution, the vapor will have a higher mole fraction of the more volatile component.
***The vapor has a different composition than the solution.
Strong Electrolyte Solutions - ANSWERSA strong electrolyte dissociates completely to form ions.
Each mole of solute gives more than 1 mol of dissolved particles
van't Hoff factor - ANSWERStakes into account the
dissociation of a strong electrolyte to predict the
effect on the solution.
Nonideal Behavior of Strong Electrolyte
, Solutions - ANSWERSIons in solution may remain
clustered near ions of
opposite charge, creating an
ionic atmosphere.
• The ions do not act
independently, and the
effective concentration of
dissolved particles is less
than expected.
Factors That Influence Reaction Rate - ANSWERSParticles must collide in order to react.
• (1) The higher the concentration of reactants, the
greater the reaction rate.
- A higher concentration of reactant particles allows a greater
number of collisions. (high collision frequency)
The physical state of the reactants influences
reaction rate. - ANSWERSSubstances must mix in order for particles to collide.
- Contact occurs only at the interface between the phase, so
vigorous stirring or even grinding may be needed.
- The more finely divide a solid or liquid reactant, and the
faster the reaction occurs.
Concentration of reactants-Why? - ANSWERSParticles must collide in order to react.
- A higher concentration of reactant particles allows a greater
number of collisions. (higher collision frequency, the greater
