Title: E5 Quiz
Course: Lab Instruments II > Section: E5: Meetings 12,13

Quiz over the objectives for Experiment Set 5.

Q: Which one of the following would lead to a decrease in retention times in a GC instrument?
- Increasing the length of the column
- Increasing the mobile phase flow rate
- Changing from a capillary to a packed column
- Changing to a lower temperature isothermal program
A: Increasing the mobile phase flow rate

Q: Which of the following GC components is NOT heated?
- Column
- Detector
- Sample injector
- Carrier gas tank
A: Carrier gas tank

Q: Which one of the following statements does NOT correctly contrast the stationary phase of GC columns?
- Packed columns typically utilize a solid stationary phase whereas capillary columns utilize a liquid stationary phase.
- Packed columns typically utilize partition chromatography whereas capillary columns utilize bonded-phase chromatography.
- The stationary phase of packed columns tends to bleed at very high temperatures whereas the stationary phase of capillary columns is relatively stable even at very high temperatures.
- The stationary phase of packed columns is distributed throughout the full diameter of the column whereas the stationary phase of capillary columns is confined to the inner wall of the column.
A: Packed columns typically utilize a solid stationary phase whereas capillary columns utilize a liquid stationary phase.

Q: Which one of the following statements correctly contrasts the typical chromatogram for the same mixture separated on a packed versus a capillary column with similar stationary phase polarities?
- Capillary column chromatograms display broader peaks.
- Capillary column chromatograms display higher resolutions.
- Capillary column chromatograms display longer retention times.
- Capillary column chromatograms display more unexpected peaks.
A: Capillary column chromatograms display higher resolutions.

Q: In a GC column with a polar liquid stationary phase, which of the following substances would most likely have the shortest retention time?
- Polar with a high vapor pressure
- Polar with a low vapor pressure
- Nonpolar with a low vapor pressure
- Nonpolar with a high vapor pressure
A: Nonpolar with a high vapor pressure

Q: Which one of the following is NOT a common GC carrier gas?
- Helium
- Hydrogen
- Nitrogen
- Oxygen
A: Oxygen

Q: Which one of the following characteristics of commonly used GC mobile phases is LEAST important in separation of analytes?
- Diffusivity
- Flow rate
- Polarity
- Viscosity
A: Polarity

Q: Which one of the following sample parameters is MOST important in determining retention times in GC?
- Polarity
- Purity
- Viscosity
- Volatility
A: Volatility

Q: Which of the following characterizes a volatile substance?
- Low vapor pressure, low boiling point
- Low vapor pressure, high boiling point
- High vapor pressure, low boiling point
- High vapor pressure, high boiling point
A: High vapor pressure, low boiling point

Q: Which statement is true regarding a programmed GC separation designed to give the best resolution?
- Column temperature starts below the boiling point of the most volatile substance in the mixture.
- Column temperature starts above the boiling point of the most volatile substance in the mixture.
- Column temperature is held constant in the middle of the range of boiling points of the substances in the mixture.
- Column temperature is held constant at the bottom of the range of boiling points of the substances in the mixture.
A: Column temperature starts below the boiling point of the most volatile substance in the mixture.

Q: Which one of the following types of injector methods results in only a fraction of the injected sample being separated on the column?
- Direct injection
- On-column injection
- Split injection
- Splitless injection
A: Split injection

Q: Only substances in the gaseous state travel through a GC column.
- True
- False
A: True

Q: A liquid state GC sample is obtained using the headspace sampling method.
- True
- False
A: False

Q: A thermal conductivity detector can be used for analysis of any type of volatile analyte.
- True
- False
A: True

Q: For a sample containing ions and organic compounds, an FID would produce peaks for the organic substances only.
- True
- False
A: True