Which one of these questions is answered incorrectly? Only one question is wrong the rest are correct. Those that are marked with – are the selected answers.
Which of the following has the largest influence on compound polarity during chromatography?
ADipole interactions
BNon-covalent interactions
CVan der Waals forces
- D. Hydrogen bonding
- What is the proper sequence of events to follow after eluting a TLC plate?
- A. Dry the plate, visualize the plate, develop the plate
BDevelop the plate, dry the plate, visualize the plate
CDry the plate, develop the plate, visualize the plate
DVisualize the plate, dry the plate, develop the plate
- Safety glasses should be worn
Auntil you finish the lab.
-B. at ALL times in the lab.
Cwhenever you are working with chemicals.
Dwhenever you are working with glassware.
Ewhen you and your partner begin the experiment.
- Disposable gloves are strongly discouraged in the laboratory because
Aaqueous chemicals may pass rapidly through the glove and cause harm to the skin.
Borganic chemicals may pass rapidly through the glove and cause harm to the skin.
Ca buildup of sweat inside the glove may cause harm to the skin.
- D. the organic chemicals may cause the gloves to dissolve.
Eit is difficult to manipulate glassware when wearing gloves.
- If you should get any laboratory chemicals on your skin,
Awipe the affected area and inform your TA.
- B. wash the affected area immediately with cold water and inform your TA.
Cwear gloves.
Dwash the affected area with cold water.
Einform your TA.
- The distribution constant
Ahas a characteristic value for a compound.
Bhas a characteristic value in a particular solvent system.
Cincreases as the concentration decreases.
-D. has a characteristic value for a compound in a particular solvent system.
- What is the most common absorbent in column chromatography?
Aalumina
Bcellulose
- C. silica gel
Dcharcoal
- A compound that moves quickly through a stationary phase will have Student Response
Aa small Rf value.
Ba small distribution constant.
Ca large distribution constant.
- D. A large Rf value.
- Venting a separatory funnel should be done by Student Response
- A. inverting and then opening the stopwingspan after shaking.
Binverting and then opening the stopwingspan before shaking.
Copening the stopwingspan after shaking.
Dopening the stopper after shaking.
Eopening the stopper before shaking.
- Addition of salt during an extraction Student Response
Aoften produces an emulsion.
Bis undesirable as it introduces impurities.
Cimproves extraction of the compound from the organic to the aqueous phase.
Dhas a negative effect on the extraction of the compound from the aqueous to the organic phase.
- E. improves extraction of the compound from the aqueous to the organic phase.
Which of the following has the largest influence on compound polarity during chromatography?
ADipole interactions
BNon-covalent interactions
CVan der Waals forces
BDevelop the plate, dry the plate, visualize the plate
CDry the plate, develop the plate, visualize the plate
DVisualize the plate, dry the plate, develop the plate
Auntil you finish the lab.
Cwhenever you are working with chemicals.
Dwhenever you are working with glassware.
Ewhen you and your partner begin the experiment.
Aaqueous chemicals may pass rapidly through the glove and cause harm to the skin.
Borganic chemicals may pass rapidly through the glove and cause harm to the skin.
Ca buildup of sweat inside the glove may cause harm to the skin.
Eit is difficult to manipulate glassware when wearing gloves.
Awipe the affected area and inform your TA.
Cwear gloves.
Dwash the affected area with cold water.
Einform your TA.
Ahas a characteristic value for a compound.
Bhas a characteristic value in a particular solvent system.
Cincreases as the concentration decreases.
Aalumina
Bcellulose
Dcharcoal
Aa small Rf value.
Ba small distribution constant.
Ca large distribution constant.
Binverting and then opening the stopwingspan before shaking.
Copening the stopwingspan after shaking.
Dopening the stopper after shaking.
Eopening the stopper before shaking.
Aoften produces an emulsion.
Bis undesirable as it introduces impurities.
Cimproves extraction of the compound from the organic to the aqueous phase.
Dhas a negative effect on the extraction of the compound from the aqueous to the organic phase.
