ACS Analytical Chemistry Exam
Questions and Answers 100% Correct
standard deviation (s) - ANSWER-the square root of the variance
% relative standard deviation (%RSD) - ANSWER-Standard deviation divided by mean
times 100
Grubbs test (Gcalc) - 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 - ANSWER-(x- xavg)/s
F Test - 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 - ANSWER-use standard solutions spanning a range of conc,
measure response
Internal standard - ANSWER-substance similar to analyte (ie deuterated); used to
normalize signal by reducing random error
Standard Addition - ANSWER-ideal for analyzing sample in a complex matrix; add
known standard to constant amount of sample; x-int =[sample]
Box car average - ANSWER-minimizes distance between data points and best fit line/
minimizes standard deviation
Limit of detection (LOD) - ANSWER-3*std dev
Limit of quantitation (LOQ) - ANSWER-10* std dev
sigma--> sigma* absorbs at - ANSWER-~100nm
proteins absorb at - ANSWER-~ 280 nm (bc of aromatic R groups)
Questions and Answers 100% Correct
standard deviation (s) - ANSWER-the square root of the variance
% relative standard deviation (%RSD) - ANSWER-Standard deviation divided by mean
times 100
Grubbs test (Gcalc) - 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 - ANSWER-(x- xavg)/s
F Test - 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 - ANSWER-use standard solutions spanning a range of conc,
measure response
Internal standard - ANSWER-substance similar to analyte (ie deuterated); used to
normalize signal by reducing random error
Standard Addition - ANSWER-ideal for analyzing sample in a complex matrix; add
known standard to constant amount of sample; x-int =[sample]
Box car average - ANSWER-minimizes distance between data points and best fit line/
minimizes standard deviation
Limit of detection (LOD) - ANSWER-3*std dev
Limit of quantitation (LOQ) - ANSWER-10* std dev
sigma--> sigma* absorbs at - ANSWER-~100nm
proteins absorb at - ANSWER-~ 280 nm (bc of aromatic R groups)
