Instrumental Analysis Exam 2 – Star questions with
verified answers
A radiationless process in which a molecule loses electronic energy
while transferring
that energy to the solvent or another solute is called...
a. vibrational relaxation
b. internal conversion
c. external conversion
d. intersystem crossing
e. predissociation
f. dissociation Ans✓✓✓ c. external conversion
A water analysis laboratory provides the
determination of magnesium and calcium in well water. Your overhead
is approximately $1,200/week. Using your autosampler tray, you can
process 400 samples/day in flame mode and 150 sample/day using
furnace
mode. Operating at full capacity, (a) what is your "breakeven" price in
dollars per measurement in flame mode at full capacity? (b) What is
your "breakeven" price per measurement in furnace mode at full
capacity? Ans✓✓✓ a. If we assume a 5 day work week the lab can
process flame mode = (5 days/work work)(400 samples/day) = 2000
samples/work week. To break even in flame mode the lab would have
to charge "breakeven" = $1,200/(2000 samples)/week = $0.60/sample
,b. If we assume a 5 day work week the lab can process furnace mode =
(5 days/work work)(150 samples/day) = 750 samples/work week. To
break even in flame mode the lab would have to charge "breakeven" =
$1,200/(750 samples)/week = $1.60/sample
Almost all methods of analysis for elemental mercury rely on the
absorbance of light at 254 nm by elemental mercury. In atomic
absorption spectroscopy, when mercury is determined what type of
atomization technique is normally used? Ans✓✓✓ a. Cold-vapor
atomization is almost exclusively for mercury analysis
An analyst needs to determine what trace elements are present in
rubber for tires. The laboratory uses a spectrometer with an arc source
(electrical discharge) in the sample introduction system. What
problems is the analyst likely to encounter in analyzing these samples?
a. rubber samples are difficult to dissolve
b. rubber is an insulator, so to conduct electricity it would have to be
mixed with another conducting material
c. rubber samples are soft and hard to grind Ans✓✓✓ b. rubber is an
insulator, so to conduct electricity it would have to be mixed with
another conducting material
Atoms are in constant motion. What is the effect of this motion on the
wavelength(s) observed by a detector when these molecules emit
radiation?
, b. atoms moving towards the detector will have shorter wavelengths,
atoms moving
away will have longer wavelengths
c. atoms moving toward the detector will have longer wavelengths,
atoms moving away will have shorter wavelengths
d. atoms moving toward or away from the detector wavelengths will
increase
e. atoms moving toward or away from the detector wa Ans✓✓✓ b.
atoms moving towards the detector will have shorter wavelengths,
atoms moving
away will have longer wavelengths
Energy dispersive system uses which of the following detectors?
a. optical detector
b. semiconductor detector
c. thermistor
d. bolometer Ans✓✓✓ b. semiconductor detector - energy dispersive
system uses semiconductor detectors. It consists of an excited source
and a sample
For a p sublevel, "I" equals __.
a. 0
b. 1
c. 2
verified answers
A radiationless process in which a molecule loses electronic energy
while transferring
that energy to the solvent or another solute is called...
a. vibrational relaxation
b. internal conversion
c. external conversion
d. intersystem crossing
e. predissociation
f. dissociation Ans✓✓✓ c. external conversion
A water analysis laboratory provides the
determination of magnesium and calcium in well water. Your overhead
is approximately $1,200/week. Using your autosampler tray, you can
process 400 samples/day in flame mode and 150 sample/day using
furnace
mode. Operating at full capacity, (a) what is your "breakeven" price in
dollars per measurement in flame mode at full capacity? (b) What is
your "breakeven" price per measurement in furnace mode at full
capacity? Ans✓✓✓ a. If we assume a 5 day work week the lab can
process flame mode = (5 days/work work)(400 samples/day) = 2000
samples/work week. To break even in flame mode the lab would have
to charge "breakeven" = $1,200/(2000 samples)/week = $0.60/sample
,b. If we assume a 5 day work week the lab can process furnace mode =
(5 days/work work)(150 samples/day) = 750 samples/work week. To
break even in flame mode the lab would have to charge "breakeven" =
$1,200/(750 samples)/week = $1.60/sample
Almost all methods of analysis for elemental mercury rely on the
absorbance of light at 254 nm by elemental mercury. In atomic
absorption spectroscopy, when mercury is determined what type of
atomization technique is normally used? Ans✓✓✓ a. Cold-vapor
atomization is almost exclusively for mercury analysis
An analyst needs to determine what trace elements are present in
rubber for tires. The laboratory uses a spectrometer with an arc source
(electrical discharge) in the sample introduction system. What
problems is the analyst likely to encounter in analyzing these samples?
a. rubber samples are difficult to dissolve
b. rubber is an insulator, so to conduct electricity it would have to be
mixed with another conducting material
c. rubber samples are soft and hard to grind Ans✓✓✓ b. rubber is an
insulator, so to conduct electricity it would have to be mixed with
another conducting material
Atoms are in constant motion. What is the effect of this motion on the
wavelength(s) observed by a detector when these molecules emit
radiation?
, b. atoms moving towards the detector will have shorter wavelengths,
atoms moving
away will have longer wavelengths
c. atoms moving toward the detector will have longer wavelengths,
atoms moving away will have shorter wavelengths
d. atoms moving toward or away from the detector wavelengths will
increase
e. atoms moving toward or away from the detector wa Ans✓✓✓ b.
atoms moving towards the detector will have shorter wavelengths,
atoms moving
away will have longer wavelengths
Energy dispersive system uses which of the following detectors?
a. optical detector
b. semiconductor detector
c. thermistor
d. bolometer Ans✓✓✓ b. semiconductor detector - energy dispersive
system uses semiconductor detectors. It consists of an excited source
and a sample
For a p sublevel, "I" equals __.
a. 0
b. 1
c. 2
