Title: CHE2DEV Quiz 5

Feedback shared by this category's questions, if partly right: 1

Q: Select the correct statement.
- The Hollow Cathode Lamp (HCL) used in Atomic Absorption Spectrometry consists of a cathode where the analyte metal ions are reduced.
- Atomic emissions from a HCL result from "sputtered" cathode atoms that emit characteristic wavelengths of light after having electrons promoted to a higher energy level from collisions with other gaseous species.
A: Atomic emissions from a HCL result from "sputtered" cathode atoms that emit characteristic wavelengths of light after having electrons promoted to a higher energy level from collisions with other gaseous species.

Q: Select the correct statement.
- Erroneous atomic emission signals from a HCL that interfere with analyte measurement can be eliminated by beam chopping of the atomic emission signal.
- Background absorption by molecular species of the HCL emission signal that interferes with analyte measurement can be nullified by using a deuterium light source to monitor this effect in the flame.
A: Background absorption by molecular species of the HCL emission signal that interferes with analyte measurement can be nullified by using a deuterium light source to monitor this effect in the flame.

Q: Select the correct statement.
- Electrothermal or graphite furnace AAS is not useful for analytes in a complicated sample matrix and has reduced detection sensitivity for most elements compared to flame AAS.
- Hydride generation AAS has improved detection sensitivity compared to flame AAS for elements like mercury and arsenic that can be introduced as a gaseous metal hydride into the flame.
A: Hydride generation AAS has improved detection sensitivity compared to flame AAS for elements like mercury and arsenic that can be introduced as a gaseous metal hydride into the flame.

Q: Select the correct statement.
- Molecular interference in the atomisation process results from organic molecules in the flame that emit light after absorbing energy from the Hollow Cathode Lamp.
- Group I and II elements in the Periodic Table have low ionisation potentials and undergo thermal ionisation in the flame that interferes with the atomisation process.
A: Group I and II elements in the Periodic Table have low ionisation potentials and undergo thermal ionisation in the flame that interferes with the atomisation process.

Q: Select the correct statement.
- Qualitative analysis in chromatography involves comparison of peaks areas of the unknown solute with that of an authentic compound.
- An infrared spectrometer can be used as a detector for quantitative measurements in chromatography.
- High Performance Liquid Chromatography using reverse phase conditions is widely used for the analysis of polar solutes in non-polar liquid phases.
- An internal standard is often added to samples in chromatography to compensate for reproducibility problems due to variations in injected sample volumes and instrumental conditions during analysis.
A: An internal standard is often added to samples in chromatography to compensate for reproducibility problems due to variations in injected sample volumes and instrumental conditions during analysis.

Q: Select the correct statement
- Flame atomic absorption spectrometry involves measurement of the emission of light from gaseous atoms of the analyte that are excited following the absorption of characteristic energy from a Hollow Cathode Lamp.
- The amount of energy from a Hollow Cathode Lamp that is absorbed by gaseous ground state atoms of the analyte can be used as a quantitative measure of the original analyte ions in solution in flame atomic absorption spectrometry.
A: The amount of energy from a Hollow Cathode Lamp that is absorbed by gaseous ground state atoms of the analyte can be used as a quantitative measure of the original analyte ions in solution in flame atomic absorption spectrometry.

Q: Select the correct statement.
- A "cool" flame temperature is used to reduce the formation of refractory oxides during the analysis of certain elements like aluminium and silicon.
- Addition to a sample of an ionisation suppression agent that is preferentially thermally ionised in the flame can aid the analysis of a readily ionised element.
A: Addition to a sample of an ionisation suppression agent that is preferentially thermally ionised in the flame can aid the analysis of a readily ionised element.

Q: Select the correct statement.
- Adsorption chromatography involves a solute interaction whereby solute molecules partition between the stationary and mobile phases.
- Ion exchange chromatography involves an electrostatic attraction between solute ions and oppositely charged sites on the stationary phase.
- Partition chromatography involves a solute interaction whereby solute molecules adsorb to the surface of the stationary phase.
A: Ion exchange chromatography involves an electrostatic attraction between solute ions and oppositely charged sites on the stationary phase.

Q: Select the correct statement.
- The pre-mix burner assembly is used to introduce large solution droplets to the flame atomiser for maximum measurement sensitivity.
- An aerosol of small solution droplets for efficient solvent evaporation is mixed with the appropriate ratio of fuel and oxidant gases in the pre-mix burner assembly.
A: An aerosol of small solution droplets for efficient solvent evaporation is mixed with the appropriate ratio of fuel and oxidant gases in the pre-mix burner assembly.

Q: Fill in each blank with a single word.
The Partition ratio (k') is a measure of the time the [...] spends between the mobile and stationary phases.
A k' value of greater than [...] but less than five indicates good chromatography.
The Resolution (Rs) describes the [...] of adjacent signals in a chromatogram.
The calculation of Rs involves the difference in [...] times and measurements of the peak base widths.
A: solute; two; separation; retention