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Lesson: Rotary Evaporation

Worksheet • 10 Questions

Q1:

Which component of a rotary evaporator is typically secured with a Keck clip?

  • AEvaporating flask
  • BSplash guard
  • CCollecting flask
  • DCondenser
  • EWater bath

Q2:

When performing a rotary evaporation, which of the following is not a reason for lowering the pressure gradually?

  • AThe solvent may freeze.
  • BThe condenser may be less effective at very low pressures.
  • CVigorous boiling may force solution out of the flask.
  • DThe rate of evaporation is more easily controlled.
  • EThe contents of the flask may foam.

Q3:

When removing a solvent in a rotary evaporator, which of the following steps is not required?

  • AThe pressure in the flask is accurately measured.
  • BThe collected solvent is disposed of safely.
  • CA Keck clip is used to secure the flask in place.
  • DThe solution is placed in a round-bottom flask.
  • EThe condenser is filled with dry ice and acetone or a water flow.

Q4:

When setting up a rotary evaporation, in which order should the following actions be performed?

  1. Lower the flask into the water bath.
  2. Turn on the pump.
  3. Start the flask rotation.
  • A2, 3, 1
  • B1, 2, 3
  • C3, 2, 1
  • D2, 1, 3
  • E3, 1, 2

Q5:

Which component of a rotary evaporator is typically secured with a pinch clamp?

  • ACollecting flask
  • BWater bath
  • CEvaporating flask
  • DCondenser
  • ESplash guard

Q6:

When performing a rotary evaporation, which of the following is the best immediate course of action if the solvent starts to bump?

  • AOpen the tap to introduce air into the system.
  • BRaise the flask from the water bath.
  • CTurn off the pump.
  • DIncrease the set pressure.
  • EStop the rotation.

Q7:

The water bath of a rotary evaporator is set to 5 0 C . Which of the following solvents could be removed safely and efficiently at this temperature?

  • AChloroform
  • BAcetone
  • CWater
  • DDiethyl ether
  • EDichloromethane

Q8:

Which piece of apparatus is not used in the normal operation of a rotary evaporator?

  • ATwo-necked flask
  • BWater bath
  • CKeck clip
  • DVacuum pump
  • ECondenser

Q9:

When performing a rotary evaporation, which of the following is not a reason for setting a low water-bath temperature?

  • AThe solvent vapor may not condense if the flask temperature is too high.
  • BHeating may cause solutes to precipitate.
  • CHeating may cause undesirable reactions of the flask contents.
  • DThe rate of evaporation is more easily controlled.
  • EVigorous boiling may force solution out of the flask if the temperature is too high.

Q10:

When a rotary evaporation is complete, in which order should the following actions be performed?

  1. Introduce air into the system.
  2. Turn off the pump.
  3. Stop the flask rotation.
  • A3, 1, 2
  • B2, 3, 1
  • C3, 2, 1
  • D1, 3, 2
  • E1, 2, 3
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