Instrumental Analysis Exam 1 questions with
verified answers
absorbance Ans✓✓✓ measure of the capacity of a substance to absorb
light of a specific wavelength
absorptivity Ans✓✓✓ measurement of how strongly a chemical
species absorbs light at a given wavelength
accuracy Ans✓✓✓ correctness of an experimental result expressed as
the closeness of the measurement to the true or accepted value
amplitude Ans✓✓✓ length from the highest point to the middle
band spectra Ans✓✓✓ encountered in spectral sources when gaseous
radicals or small molecules are present; bands arise from numerous
quantized vibrational levels that are superimposed on the ground-state
electronic energy level of a molecule
Be familiar with the basic components of optical instruments and the
arrangement of these components for various types of applications.
Ans✓✓✓ 1. Source - a stable source of radiant energy
2. Wavelength selector - a device that isolates a restricted region of the
spectrum for measurement
3. Sample - needs a transparent container for holding the sample
, 4. Detector - a radiation detector which converts radiant energy to a
usable signal (usually electrical)
5. Signal processor readout - for most modern instruments this is a
computer
For an emission flame photometer, there's the sample under the flame,
then the flame, then the wavelength selector, then the detector, then
the signal processor readout.
For the flame AA, it's the lamp as the source, then the sample under
the flame, then the wavelength selector, then the detector, then the
signal processor readout.
For the absorption spectrometer, it's the lamp source, wavelength
selector, sample, detector, then signal processor and readout. This is
like what was used in biochem lab.
For the fluorescence or scattering spectrometer, it's the source at a 90
degree angle to the sample, then the wavelength selector, then the
detector, then the signal processor readout.
Be familiar with the various types of materials used for construction of
the optical components and what wavelength regions they are useful
for. Ans✓✓✓ Lithium fluoride for UV-Vis windows, hollow cathode
lamps for sources.
IR can only have inorganic salts like NaCl for the windows, nichrome
wire for the source.
verified answers
absorbance Ans✓✓✓ measure of the capacity of a substance to absorb
light of a specific wavelength
absorptivity Ans✓✓✓ measurement of how strongly a chemical
species absorbs light at a given wavelength
accuracy Ans✓✓✓ correctness of an experimental result expressed as
the closeness of the measurement to the true or accepted value
amplitude Ans✓✓✓ length from the highest point to the middle
band spectra Ans✓✓✓ encountered in spectral sources when gaseous
radicals or small molecules are present; bands arise from numerous
quantized vibrational levels that are superimposed on the ground-state
electronic energy level of a molecule
Be familiar with the basic components of optical instruments and the
arrangement of these components for various types of applications.
Ans✓✓✓ 1. Source - a stable source of radiant energy
2. Wavelength selector - a device that isolates a restricted region of the
spectrum for measurement
3. Sample - needs a transparent container for holding the sample
, 4. Detector - a radiation detector which converts radiant energy to a
usable signal (usually electrical)
5. Signal processor readout - for most modern instruments this is a
computer
For an emission flame photometer, there's the sample under the flame,
then the flame, then the wavelength selector, then the detector, then
the signal processor readout.
For the flame AA, it's the lamp as the source, then the sample under
the flame, then the wavelength selector, then the detector, then the
signal processor readout.
For the absorption spectrometer, it's the lamp source, wavelength
selector, sample, detector, then signal processor and readout. This is
like what was used in biochem lab.
For the fluorescence or scattering spectrometer, it's the source at a 90
degree angle to the sample, then the wavelength selector, then the
detector, then the signal processor readout.
Be familiar with the various types of materials used for construction of
the optical components and what wavelength regions they are useful
for. Ans✓✓✓ Lithium fluoride for UV-Vis windows, hollow cathode
lamps for sources.
IR can only have inorganic salts like NaCl for the windows, nichrome
wire for the source.
