Sample pre-lab quiz for Distillation (and Gas Chromatography) experiment.

1) The boiling point is measured:

1. above the surface of the liquid
2. in the boiling liquid itself
3. in the receiving flask
4. with a thermometer external to the distillation apparatus

2) If a compound boils at 100 degrees at 760 mm, its boiling point at 725 mm will be:

1. lower
2. higher
3. the same
4. cannot predict

3) In a distillation of a mixture of two components, the first compound to condense into the receiving flask will be:

1. the one with the lower melting point
2. the one with the higher melting point
3. the one with the lower boiling point
4. the one with the higher boiling point

4) The greater the surface area of the packing of the fractionating column,

1. the greater its efficiency
2. the lower its efficiency
3. efficiency does not depend on the surface area of the column
4. the faster the distillation will proceed

5) Ideally, in a gas chromatographic technique the individual compounds in a sample:

1. leave the adsorbent in a different physical state than that in which they entered it
2. become separated from each other as they pass through the adsorbent
3. become bonded to one another
4. attach irreversibly to the adsorbent

6) In gas chromatography, the sample is injected with a syringe into the gas chromatograph:

1. directly onto the column
2. through the heated injection port
3. into the detector
4. into the recorder

7) The vaporized GC sample is carried through the heated column by:

1. a stream of air
2. an inert carrier gas (helium or nitrogen)
3. the adsorbent
4. steam

Answers.