ACS ANALYTICAL CHEMISTRY 2025
GRADED A, WITH ACTUAL QUESTIONS
AND CORRECT ANSWERS
standard deviation (s) - CORRECT ANSWER-the square root of the variance
% relative standard deviation (%RSD) - CORRECT ANSWER-Standard deviation
divided by mean times 100
Grubbs test (Gcalc) - CORRECT ANSWER-|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 ANSWER-(x- xavg)/s
F Test - CORRECT ANSWER-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 ANSWER-use standard solutions spanning a range
of conc, measure response
Internal standard - CORRECT ANSWER-substance similar to analyte (ie
deuterated); used to normalize signal by reducing random error
Standard Addition - CORRECT ANSWER-ideal for analyzing sample in a complex
matrix; add known standard to constant amount of sample; x-int =[sample]
Box car average - CORRECT ANSWER-minimizes distance between data points
and best fit line/ minimizes standard deviation
Limit of detection (LOD) - CORRECT ANSWER-3*std dev
Limit of quantitation (LOQ) - CORRECT ANSWER-10* std dev
sigma--> sigma* absorbs at - CORRECT ANSWER-~100nm
proteins absorb at - CORRECT ANSWER-~ 280 nm (bc of aromatic R groups)
d-->d absorb - CORRECT ANSWER-visible light
(transition metals)
IR spectroscopy - CORRECT ANSWER-responds to change in dipole moment
GRADED A, WITH ACTUAL QUESTIONS
AND CORRECT ANSWERS
standard deviation (s) - CORRECT ANSWER-the square root of the variance
% relative standard deviation (%RSD) - CORRECT ANSWER-Standard deviation
divided by mean times 100
Grubbs test (Gcalc) - CORRECT ANSWER-|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 ANSWER-(x- xavg)/s
F Test - CORRECT ANSWER-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 ANSWER-use standard solutions spanning a range
of conc, measure response
Internal standard - CORRECT ANSWER-substance similar to analyte (ie
deuterated); used to normalize signal by reducing random error
Standard Addition - CORRECT ANSWER-ideal for analyzing sample in a complex
matrix; add known standard to constant amount of sample; x-int =[sample]
Box car average - CORRECT ANSWER-minimizes distance between data points
and best fit line/ minimizes standard deviation
Limit of detection (LOD) - CORRECT ANSWER-3*std dev
Limit of quantitation (LOQ) - CORRECT ANSWER-10* std dev
sigma--> sigma* absorbs at - CORRECT ANSWER-~100nm
proteins absorb at - CORRECT ANSWER-~ 280 nm (bc of aromatic R groups)
d-->d absorb - CORRECT ANSWER-visible light
(transition metals)
IR spectroscopy - CORRECT ANSWER-responds to change in dipole moment
