INSTRUMENTAL ANALYSIS FINAL
EXAM QUESTIONS AND CORRECT
ANSWERS
TA2orA2F:A2
HyphenatedA2techniquesA2combineA2chromatographicA2andA2spectralA2methodsA2toA2expl
oitA2advantagesA2ofA2both,A2suchA2asA2GC-
MS.A2ChromatographyA2producesA2pureA2orA2nearlyA2pureA2fractionsA2ofA2chemicalA2com
ponentsA2inA2aA2mixture.A2SpectroscopyA2producesA2selectiveA2informationA2forA2identifica
tionA2usingA2standardsA2orA2libraryA2spectraA2-A2Ans--True
TA2orA2F:A2TheA2figureA2onA2theA2rightA2indicatesA2poorA2accuracyA2andA2goodA2precisionA2
-A2Ans--False
TA2orA2F:A2Signal-to-
noiseA2ratioA2isA2aA2measureA2usedA2inA2scienceA2andA2engineeringA2thatA2comparesA2the
A2levelA2ofA2aA2desiredA2signalA2toA2theA2levelA2ofA2backgroundA2noise.A2SNRA2isA2definedA
2asA2theA2ratioA2ofA2theA2noiseA2powerA2toA2theA2signalA2power,A2oftenA2expressedA2inA2de
cibels.A2-A2Ans--False
TA2orA2F:A2SmallA2measurementA2uncertaintiesA2areA2normalA2duringA2calibration.A2InA2ord
erA2toA2determineA2theA2actualA2concentration-
absorbanceA2responseA2usingA2Beer'sA2Law,A2performA2aA2least-
squaresA2fitA2ofA2theA2dataA2pointsA2-A2Ans--True
TA2orA2F:A2LengthA2(meter),A2forceA2(Newton),A2andA2temperatureA2(CelsiusA2degree)A2are
A2SIA2baseA2unitsA2whileA2densityA2andA2pressureA2(Pascal)A2areA2SIA2derivedA2unitsA2-
A2Ans--False
EquationA2A=abcA2whereA2AA2isA2absorbance,A2aA2molarA2absorptivity,A2andA2cA2concentr
ation.A2ThisA2equationA2isA2knownA2asA2-A2Ans--Beer'sA2Law
TheA2transitionA2ofA2electrons.A2ItA2isA2betterA2toA2explainA2asA2___A2lightA2-A2Ans--
Fluorescence
WhatA2isA2theA2correctA2readingA2ofA2theA2buret?A2-A2Ans--29.44A2mL
AA2studentA2needsA215.0A2gA2ofA2ethylA2alcoholA2forA2anA2experiment.A2IfA2he/
sheA2findsA2theA2densityA2(d=A20.789A2g/
mL,A2atA220C)A2onA2theA2reagentA2bottleA2label,A2howA2manyA2millilitersA2(mL)A2ofA2theA2liq
uidA2areA2neededA2atA220C?A2-A2Ans--19.0A2mL
, AsA2aA2consequenceA2ofA2Snell'sA2Law,A2lightA2wavesA2transitioningA2intoA2aA2mediumA2of
A2higherA2refractiveA2willA2tendA2toA2beA2-A2Ans--RefractedA2towardA2theA2normalA2axis
DescribeA2theA2relationshipA2betweenA2wavelengthA2andA2frequencyA2ofA2lightA2-A2Ans--
TheA2shorterA2theA2wavelengthA2theA2higherA2theA2frequency,A2theA2widerA2theA2waveleng
thA2theA2lowerA2theA2frequency
SmallA2measurementA2uncertaintiesA2areA2normalA2duringA2calibration.A2InA2orderA2toA2det
ermineA2theA2actualA2concentration-
absorbanceA2responseA2usingA2Beer'sA2Law,A2performA2aA2least-
squaresA2fitA2toA2theA2dataA2points.A2ThisA2isA2-A2Ans--Zero-concentration
RefersA2toA2aA2defectA2inA2aA2lensA2designA2whichA2causesA2lightA2toA2spreadA2outA2instea
dA2ofA2focusingA2toA2formA2aA2sharpA2imageA2-A2Ans--OpticA2Aberration
ImagesA2producedA2byA2divergingA2lightA2raysA2(appearingA2whereA2theA2lightA2raysA2see
mA2toA2converge)A2isA2referredA2toA2asA2aA2___,A2suchA2asA2anA2imageA2fromA2aA2lightA2mi
croscopeA2-A2Ans--VirtualA2image
Snell'sA2LawA2equationA2isA2expressedA2asA2-A2Ans--n1sin1=n2sin2
InA2anA2GCA2analysis,A2aA2chemistA2observedA2twoA2adjacentA2peaks.A2PeakA2AA2wasA2atA
216.8A2minutesA2andA2peakA2BA2wasA2atA221.4A2minutes.A2TheA2chemistA2measuredA2theA2
peakA2widthA2nearA2theA2baselineA2andA2foundA2peakA2AA2wasA23.4A2minutesA2andA2peakA
2BA2wasA23.6A2minutes.A2CalculateA2theA2resolutionA2-A2Ans--1.31
WereA2theA2twoA2peaksA2wellA2separated?A2-A2Ans--
TheA2calculationA2disclosedA2thatA2theA2twoA2peaksA2wereA21.31.A2ThisA2showsA2thatA2two
A2peaksA2wereA2wellA2separated.
Why?A2-A2Ans--
TheA2calculationA2showsA2thatA2theA2twoA2peaksA2wereA2notA2onA2topA2ofA2eachA2other
TA2orA2F:A2AA2flameA2atomicA2absorptionA2methodA2canA2beA2usedA2toA2distinguishA2betwe
enA2calciumA2chlorideA2andA2calciumA2nitrateA2-A2Ans--False
TA2orA2F:A2TheA2absorbanceA2peaksA2forA2atomicA2absorptionA2spectroscopyA2areA2muchA
2widerA2thanA2thatA2forA2molecularA2spectroscopy,A2absorbanceA2(y-
axis)A2versusA2wavelengthA2(x-axis)A2-A2Ans--False
TA2orA2F:A2AccordingA2toA2theA2RydbergA2Equation,A2theA2transitionsA2ofA2theA2electronsA2f
romA2theA2excitedA2stateA2n4A2toA2theA2groundA2stateA2n1A2resultA2inA2emittingA2theA2lights
A2inA2theA2visibleA2range,A2forA2example,A2n4>n1A2-A2Ans--False
EXAM QUESTIONS AND CORRECT
ANSWERS
TA2orA2F:A2
HyphenatedA2techniquesA2combineA2chromatographicA2andA2spectralA2methodsA2toA2expl
oitA2advantagesA2ofA2both,A2suchA2asA2GC-
MS.A2ChromatographyA2producesA2pureA2orA2nearlyA2pureA2fractionsA2ofA2chemicalA2com
ponentsA2inA2aA2mixture.A2SpectroscopyA2producesA2selectiveA2informationA2forA2identifica
tionA2usingA2standardsA2orA2libraryA2spectraA2-A2Ans--True
TA2orA2F:A2TheA2figureA2onA2theA2rightA2indicatesA2poorA2accuracyA2andA2goodA2precisionA2
-A2Ans--False
TA2orA2F:A2Signal-to-
noiseA2ratioA2isA2aA2measureA2usedA2inA2scienceA2andA2engineeringA2thatA2comparesA2the
A2levelA2ofA2aA2desiredA2signalA2toA2theA2levelA2ofA2backgroundA2noise.A2SNRA2isA2definedA
2asA2theA2ratioA2ofA2theA2noiseA2powerA2toA2theA2signalA2power,A2oftenA2expressedA2inA2de
cibels.A2-A2Ans--False
TA2orA2F:A2SmallA2measurementA2uncertaintiesA2areA2normalA2duringA2calibration.A2InA2ord
erA2toA2determineA2theA2actualA2concentration-
absorbanceA2responseA2usingA2Beer'sA2Law,A2performA2aA2least-
squaresA2fitA2ofA2theA2dataA2pointsA2-A2Ans--True
TA2orA2F:A2LengthA2(meter),A2forceA2(Newton),A2andA2temperatureA2(CelsiusA2degree)A2are
A2SIA2baseA2unitsA2whileA2densityA2andA2pressureA2(Pascal)A2areA2SIA2derivedA2unitsA2-
A2Ans--False
EquationA2A=abcA2whereA2AA2isA2absorbance,A2aA2molarA2absorptivity,A2andA2cA2concentr
ation.A2ThisA2equationA2isA2knownA2asA2-A2Ans--Beer'sA2Law
TheA2transitionA2ofA2electrons.A2ItA2isA2betterA2toA2explainA2asA2___A2lightA2-A2Ans--
Fluorescence
WhatA2isA2theA2correctA2readingA2ofA2theA2buret?A2-A2Ans--29.44A2mL
AA2studentA2needsA215.0A2gA2ofA2ethylA2alcoholA2forA2anA2experiment.A2IfA2he/
sheA2findsA2theA2densityA2(d=A20.789A2g/
mL,A2atA220C)A2onA2theA2reagentA2bottleA2label,A2howA2manyA2millilitersA2(mL)A2ofA2theA2liq
uidA2areA2neededA2atA220C?A2-A2Ans--19.0A2mL
, AsA2aA2consequenceA2ofA2Snell'sA2Law,A2lightA2wavesA2transitioningA2intoA2aA2mediumA2of
A2higherA2refractiveA2willA2tendA2toA2beA2-A2Ans--RefractedA2towardA2theA2normalA2axis
DescribeA2theA2relationshipA2betweenA2wavelengthA2andA2frequencyA2ofA2lightA2-A2Ans--
TheA2shorterA2theA2wavelengthA2theA2higherA2theA2frequency,A2theA2widerA2theA2waveleng
thA2theA2lowerA2theA2frequency
SmallA2measurementA2uncertaintiesA2areA2normalA2duringA2calibration.A2InA2orderA2toA2det
ermineA2theA2actualA2concentration-
absorbanceA2responseA2usingA2Beer'sA2Law,A2performA2aA2least-
squaresA2fitA2toA2theA2dataA2points.A2ThisA2isA2-A2Ans--Zero-concentration
RefersA2toA2aA2defectA2inA2aA2lensA2designA2whichA2causesA2lightA2toA2spreadA2outA2instea
dA2ofA2focusingA2toA2formA2aA2sharpA2imageA2-A2Ans--OpticA2Aberration
ImagesA2producedA2byA2divergingA2lightA2raysA2(appearingA2whereA2theA2lightA2raysA2see
mA2toA2converge)A2isA2referredA2toA2asA2aA2___,A2suchA2asA2anA2imageA2fromA2aA2lightA2mi
croscopeA2-A2Ans--VirtualA2image
Snell'sA2LawA2equationA2isA2expressedA2asA2-A2Ans--n1sin1=n2sin2
InA2anA2GCA2analysis,A2aA2chemistA2observedA2twoA2adjacentA2peaks.A2PeakA2AA2wasA2atA
216.8A2minutesA2andA2peakA2BA2wasA2atA221.4A2minutes.A2TheA2chemistA2measuredA2theA2
peakA2widthA2nearA2theA2baselineA2andA2foundA2peakA2AA2wasA23.4A2minutesA2andA2peakA
2BA2wasA23.6A2minutes.A2CalculateA2theA2resolutionA2-A2Ans--1.31
WereA2theA2twoA2peaksA2wellA2separated?A2-A2Ans--
TheA2calculationA2disclosedA2thatA2theA2twoA2peaksA2wereA21.31.A2ThisA2showsA2thatA2two
A2peaksA2wereA2wellA2separated.
Why?A2-A2Ans--
TheA2calculationA2showsA2thatA2theA2twoA2peaksA2wereA2notA2onA2topA2ofA2eachA2other
TA2orA2F:A2AA2flameA2atomicA2absorptionA2methodA2canA2beA2usedA2toA2distinguishA2betwe
enA2calciumA2chlorideA2andA2calciumA2nitrateA2-A2Ans--False
TA2orA2F:A2TheA2absorbanceA2peaksA2forA2atomicA2absorptionA2spectroscopyA2areA2muchA
2widerA2thanA2thatA2forA2molecularA2spectroscopy,A2absorbanceA2(y-
axis)A2versusA2wavelengthA2(x-axis)A2-A2Ans--False
TA2orA2F:A2AccordingA2toA2theA2RydbergA2Equation,A2theA2transitionsA2ofA2theA2electronsA2f
romA2theA2excitedA2stateA2n4A2toA2theA2groundA2stateA2n1A2resultA2inA2emittingA2theA2lights
A2inA2theA2visibleA2range,A2forA2example,A2n4>n1A2-A2Ans--False
