Exam 2: Spectral Techniques

In UV/Visible spectrophotometry, absorption spectra consist of relatively broad bands of absorption, whereas in atomic absorption spectrophotometry, line spectra consist of lines of absorption that are on the order of 0.001 to 0.01 nm in width.Which of the following provides the correct explanation for this difference in width of absorption bands?

As part of the development of a new spectrophotometric assay, an absorption spectrum was recorded.Which of the following describes the purpose for this absorption spectrum?

A linear relationship between concentration and fluorescence intensity is seen as long as solutions being quantified have an absorbance of:

A system in which the light intensity of the wavelength produced by each atom is directly proportional to the number of atoms emitting energy, which in turn is directly related to the concentration of the compound being measured, describes: 1)atomic absorption spectrophotometry 2)atomic emission flame photometry 3)UV/Visible spectrophotometry 4)fluorometry

The flame in atomic absorption spectrophotometry is used to:

______ techniques measure light scattered by a particulate solution, and ______ techniques measure a decrease in light transmission through a particulate solution._____ measurements can be performed on a basic UV/Visible spectrophotometer.

Absorbance is _________ related to percent transmittance.

Suppose the absorbance for a known solution was calculated to be 0.333.The solution was measured on a spectrophotometer, and the measured absorbance was 0.321.The solution was prepared again and gave the same absorbance reading of 0.321.Which of the following explanations would most accurately explain the difference between the calculated absorbance and the measured absorbance?

What are the units for a (absorptivity) in Beer's law when c (concentration) is expressed in g/dL, and b (path length) is expressed in cm?

What would happen to the percent transmittance of a sample that was read in a cuvette with fingerprints on the optical surface?

The percent transmittance of a solution is 50%.Calculate the absorbance.

Once a molecule absorbs electromagnetic radiation, it becomes unstable and spontaneously returns to its unexcited, or ground, state by which of the following processes?

The wavelength of electromagnetic radiation is: 1)directly proportional to the energy of a photon 2)inversely proportional to the energy of a photon 3)directly proportional to the frequency of a photon 4)inversely proportional to the frequency of a photon

A solution of chloramphenicol (MW 323.1) in water gave an absorbance of 0.610 at 278 nm in a 1-cm cuvette; the concentration was 0.02 mg/mL.What is the molar absorptivity of chloramphenicol?

In comparing nephelometry and turbidity, nephelometric measurements should demonstrate ______ sensitivity, and turbidimetric measurements should demonstrate ______ sensitivity.In practice, turbidimetric measurements have been found to demonstrate ______ sensitivity.

Any radiant energy that is measured by the detector but outside the spectral region isolated by the monochromator of the instrument is referred to as ______.As this increases, Beer's law linearity will ______.

The light source most frequently used for spectrophotometric analysis in the UV region is a ______ lamp and in the visible region, a _____ lamp.

In the clinical laboratory, the primary problem with the use of fluorescent techniques is that:

If a glucose standard has an absorbance of 0.480, and an unknown has an absorbance of 0.120, which of the following best describes the unknown's glucose concentration?

Holmium oxide and didymium filters are used to perform which of the following quality-control checks on spectrophotometers?