CHEM 212 ACS EXAM question with answers
|\ |\ |\ |\ |\ |\
Colligative Properties |\
***Non-volatile non-electrolyte Solute - CORRECT |\ |\ |\ |\ |\
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 - CORRECT 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 - CORRECT ANSWERS ✔✔A
|\ |\ |\ |\ |\ |\ |\
strong electrolyte dissociates completely to form ions.
|\ |\ |\ |\ |\ |\ |\
Each mole of solute gives more than 1 mol of dissolved
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
particles
van't Hoff factor - CORRECT ANSWERS ✔✔takes into
|\ |\ |\ |\ |\ |\ |\ |\
account the |\
dissociation of a strong electrolyte to predict the |\ |\ |\ |\ |\ |\ |\
effect on the solution.
|\ |\ |\
Nonideal Behavior of Strong Electrolyte
|\ |\ |\ |\
Solutions - CORRECT ANSWERS ✔✔Ions 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 - CORRECT
|\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔Particles 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. - CORRECT ANSWERS ✔✔Substances 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? - CORRECT ANSWERS |\ |\ |\ |\ |\ |\
✔✔Particles must collide in order to react. |\ |\ |\ |\ |\ |\
- A higher concentration of reactant particles allows a
|\ |\ |\ |\ |\ |\ |\ |\ |\
greater
number of collisions. (higher collision frequency, the
|\ |\ |\ |\ |\ |\ |\
greater
the reaction rate.)
|\ |\
The higher the temperature, the greater the
|\ |\ |\ |\ |\ |\
|\ |\ |\ |\ |\ |\
Colligative Properties |\
***Non-volatile non-electrolyte Solute - CORRECT |\ |\ |\ |\ |\
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 - CORRECT 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 - CORRECT ANSWERS ✔✔A
|\ |\ |\ |\ |\ |\ |\
strong electrolyte dissociates completely to form ions.
|\ |\ |\ |\ |\ |\ |\
Each mole of solute gives more than 1 mol of dissolved
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
particles
van't Hoff factor - CORRECT ANSWERS ✔✔takes into
|\ |\ |\ |\ |\ |\ |\ |\
account the |\
dissociation of a strong electrolyte to predict the |\ |\ |\ |\ |\ |\ |\
effect on the solution.
|\ |\ |\
Nonideal Behavior of Strong Electrolyte
|\ |\ |\ |\
Solutions - CORRECT ANSWERS ✔✔Ions 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 - CORRECT
|\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔Particles 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. - CORRECT ANSWERS ✔✔Substances 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? - CORRECT ANSWERS |\ |\ |\ |\ |\ |\
✔✔Particles must collide in order to react. |\ |\ |\ |\ |\ |\
- A higher concentration of reactant particles allows a
|\ |\ |\ |\ |\ |\ |\ |\ |\
greater
number of collisions. (higher collision frequency, the
|\ |\ |\ |\ |\ |\ |\
greater
the reaction rate.)
|\ |\
The higher the temperature, the greater the
|\ |\ |\ |\ |\ |\
