ACS ANALYTICAL CHEMISTRY |2024
/2025 UPDATE |REAL EXAM QUESTIONS
AND VERIFIED ANSWERS/100%
CORRECT| WELL GRADED A+
Raman - CORRECT ANSWERS-responds to change in polarizability
photomultiplier tube - CORRECT ANSWERS-detects single photon, is highly sensitive
Jablonski Diagram - CORRECT ANSWERS-shows movement from ground state to
excited state
Fluorescence - CORRECT ANSWERS-occurs when LUMO--> HOMO releases energy;
generally occurs in rigid molecules
X ray fluorescence - CORRECT ANSWERS-Useful when sample cannot be put into
sol'n
capacity factor (k') - CORRECT ANSWERS-tells efficiency of a separation
k'= time in SP /time for MP to elute= mol SP/mol MP
Van Deemter Equation - CORRECT ANSWERS-
A (in van deemter Eq) - CORRECT ANSWERS-accounts for path
A=2(lambda)dp
decrease particle diameter, increase speed of separation
B (in van deemter Eq) - CORRECT ANSWERS-accounts for diffusion
B= 2(gamma) Dm
affected by temp, [ ], solubility, density, viscosity,
gamma-- channel uniformity
C (in van deemter Eq) - CORRECT ANSWERS-accounts for equilibration
, Cs = f'(k') * (df^2/Ds)
Cm = f(k') * (r^2/Dm)
Gas chromatography - CORRECT ANSWERS-A term is eliminated
Liquid chromatography - CORRECT ANSWERS-no terms eliminated
capillary electrophoresis - CORRECT ANSWERS-A and C terms eliminate; VERY
efficient
standard deviation (s) - CORRECT ANSWERS-the square root of the variance
% relative standard deviation (%RSD) - CORRECT ANSWERS-Standard deviation
divided by mean times 100
Grubbs test (Gcalc) - CORRECT ANSWERS-|Questionable value - mean/ std dev|
If that is larger than the Gtable value then the value is thrown out. Locate Gtable value
based on number of values in data set.
Used to define outliers
z score - CORRECT ANSWERS-(x- xavg)/s
F Test - CORRECT ANSWERS-used to compare precision
(s2)^2/(s1)^2 (should always be >1)
Use n-1 to find on table.
Fcalc> Ftable -- There is some noise or error
External standard - CORRECT ANSWERS-use standard solutions spanning a range of
conc, measure response
Internal standard - CORRECT ANSWERS-substance similar to analyte (ie deuterated);
used to normalize signal by reducing random error
Standard Addition - CORRECT ANSWERS-ideal for analyzing sample in a complex
matrix; add known standard to constant amount of sample; x-int =[sample]
Box car average - CORRECT ANSWERS-minimizes distance between data points and
best fit line/ minimizes standard deviation
Limit of detection (LOD) - CORRECT ANSWERS-3*std dev
Limit of quantitation (LOQ) - CORRECT ANSWERS-10* std dev
/2025 UPDATE |REAL EXAM QUESTIONS
AND VERIFIED ANSWERS/100%
CORRECT| WELL GRADED A+
Raman - CORRECT ANSWERS-responds to change in polarizability
photomultiplier tube - CORRECT ANSWERS-detects single photon, is highly sensitive
Jablonski Diagram - CORRECT ANSWERS-shows movement from ground state to
excited state
Fluorescence - CORRECT ANSWERS-occurs when LUMO--> HOMO releases energy;
generally occurs in rigid molecules
X ray fluorescence - CORRECT ANSWERS-Useful when sample cannot be put into
sol'n
capacity factor (k') - CORRECT ANSWERS-tells efficiency of a separation
k'= time in SP /time for MP to elute= mol SP/mol MP
Van Deemter Equation - CORRECT ANSWERS-
A (in van deemter Eq) - CORRECT ANSWERS-accounts for path
A=2(lambda)dp
decrease particle diameter, increase speed of separation
B (in van deemter Eq) - CORRECT ANSWERS-accounts for diffusion
B= 2(gamma) Dm
affected by temp, [ ], solubility, density, viscosity,
gamma-- channel uniformity
C (in van deemter Eq) - CORRECT ANSWERS-accounts for equilibration
, Cs = f'(k') * (df^2/Ds)
Cm = f(k') * (r^2/Dm)
Gas chromatography - CORRECT ANSWERS-A term is eliminated
Liquid chromatography - CORRECT ANSWERS-no terms eliminated
capillary electrophoresis - CORRECT ANSWERS-A and C terms eliminate; VERY
efficient
standard deviation (s) - CORRECT ANSWERS-the square root of the variance
% relative standard deviation (%RSD) - CORRECT ANSWERS-Standard deviation
divided by mean times 100
Grubbs test (Gcalc) - CORRECT ANSWERS-|Questionable value - mean/ std dev|
If that is larger than the Gtable value then the value is thrown out. Locate Gtable value
based on number of values in data set.
Used to define outliers
z score - CORRECT ANSWERS-(x- xavg)/s
F Test - CORRECT ANSWERS-used to compare precision
(s2)^2/(s1)^2 (should always be >1)
Use n-1 to find on table.
Fcalc> Ftable -- There is some noise or error
External standard - CORRECT ANSWERS-use standard solutions spanning a range of
conc, measure response
Internal standard - CORRECT ANSWERS-substance similar to analyte (ie deuterated);
used to normalize signal by reducing random error
Standard Addition - CORRECT ANSWERS-ideal for analyzing sample in a complex
matrix; add known standard to constant amount of sample; x-int =[sample]
Box car average - CORRECT ANSWERS-minimizes distance between data points and
best fit line/ minimizes standard deviation
Limit of detection (LOD) - CORRECT ANSWERS-3*std dev
Limit of quantitation (LOQ) - CORRECT ANSWERS-10* std dev
