Title: E1 Quiz
Course: Lab Instruments II > Section: E1: Meetings 1,2,3,4

Quiz over the Experiment Set 1 objectives.

Q: The process of converting molecules, atoms, etc. in any state of matter to free ions or atoms in the gaseous state is termed______.
- Atomization
- Gasification
- Ionization
- Vaporization
A: Atomization

Q: Which of the following spectroscopy techniques does NOT utilize a light source at the beginning of the optical pathway?
- Graphite furnace spectroscopy
- ICP spectroscopy
- IR spectroscopy
- UV-Vis spectroscopy
A: ICP spectroscopy

Q: Identify the statement that LEAST accurately describes analysis by graphite furnace atomic absorption spectroscopy.
- Light passes through the sample in the gaseous phase.
- A nebulizer aspirates the sample into a mixing chamber.
- An inert gas circulates inside and outside the sample compartment.
- The sample is introduced to the spectrometer in the solution phase.
A: A nebulizer aspirates the sample into a mixing chamber.

Q: Identify the statement that LEAST accurately describes analysis by flame atomic absorption spectroscopy.
- The length of the flame is the pathlength in Beer’s Law.
- Only a few microliters of sample are required for analysis.
- Acetylene and nitrous oxide are a common fuel-oxidant mixture.
- A waste receptacle attached to the instrument must be emptied regularly.
A: Only a few microliters of sample are required for analysis.

Q: Which one of the following is a light source used in atomic absorption spectroscopy?
- Xenon arc lamp
- Hallow cathode lamp
- Tungsten filament lamp
- A light source is not used
A: Hallow cathode lamp

Q: Choose the one statement below that best characterizes the purpose of the flame in flame AA spectroscopy.
- Evaporate the solvent away from the analyte
- Convert the analyte to free gas atoms/ions
- Create excited state electrons in the analyte
- Evaporate the solvent and convert the analyte to free gas atoms/ions
- Evaporate the solvent, convert the analyte to free gas atoms/ions, and create excited state electrons
A: Evaporate the solvent and convert the analyte to free gas atoms/ions

Q: Choose the one statement below that best characterizes the purpose of the plasma torch in ICP spectroscopy.
- Evaporate the solvent away from the analyte
- Convert the analyte to free gas atoms/ions
- Create excited state electrons in the analyte
- Evaporate the solvent and convert the analyte to free gas atoms/ions
- Evaporate the solvent, convert the analyte to free gas atoms/ions, and create excited state electrons
A: Evaporate the solvent, convert the analyte to free gas atoms/ions, and create excited state electrons

Q: Which one of the following statements comparing atomic absorption and UV-Vis spectroscopy is FALSE?
- In both AA spectroscopy and UV-Vis spectroscopy, electrons become excited when they absorb light in the UV-Vis range from the light source.
- In AA spectroscopy the light source emits spectral lines whereas in UV-Vis spectroscopy the light source emits a broad continuum of wavelengths.
- In AA spectroscopy the amount of light absorbed by the sample is measured whereas in UV-Vis spectroscopy the intensity of light emitted is measured.
- In AA spectroscopy wavelength selection occurs after the source light has passed through the sample, whereas in UV-Vis spectroscopy wavelength selection occurs before the source light passes through the sample.
A: In AA spectroscopy the amount of light absorbed by the sample is measured whereas in UV-Vis spectroscopy the intensity of light emitted is measured.

Q: Which of the following correctly describes how to determine the concentration of an unknown using the standard additions method?
- The concentration of unknown is the x-intercept (y = 0).
- The concentration of unknown is the y-intercept (x = 0).
- The concentration of unknown is found by plugging its absorbance reading into the equation of the line and solving for x.
- The concentration of unknown is found by plugging its absorbance reading into the equation of the line and solving for y.
A: The concentration of unknown is the x-intercept (y = 0).

Q: Which one of the following is used to correct for spectral interferences?
- Adding a matrix modifier to the sample
- Running a background correct technique
- Running the spectroscopic analysis at a different temperature
- Adding a fixed quantity of sample to each of the standard solutions
A: Running a background correct technique

Q: Which one of the following statements about a plasma torch is FALSE?
- It excites electrons in more atoms in a sample than a flame does.
- It excites electrons in a larger variety of atoms than a flame does.
- It is created by resistive heating when a gas is coupled to a magnetic field.
- It forms when a fuel and oxidant burn in the presence of a magnetic field.
A: It forms when a fuel and oxidant burn in the presence of a magnetic field.

Q: Both atomic absorption and emission spectroscopy techniques require atomization of the sample.
- True
- False
A: True

Q: The detection limit of an instrument is reported as the concentration that produces an absorption of 1%.
- True
- False
A: False

Q: The appropriate hollow cathode tube to use for atomic absorption spectrometric analysis is the one that contains a cathode made of the same metal as the analyte.
- True
- False
A: True

Q: Graphite furnace AA will give a stronger signal than flame AA for the same analyte at the same concentration.
- True
- False
A: True