Analytical chemistry ACS Correctly Solved/ latest 2024/2025

Analytical chemistry ACS Correctly Solved E relative - Answer -(|x1-x(true)|)/x(true) *100 standard deviation - Answer -sqrt((x1-x)^(2)+(x2-x)^(2))/(n-1) relative standard deviation - Answer -(s/x(mean))*100 relative uncertainty - Answer -(abs uncertainty)/measured value How are vol pipets calibrated? - Answer -For last drop to not be forced out TC - Answer -to contain TD - Answer -to deliver Tolerance - Answer -max permissible deviation of measured value propagation of uncertainty add or sub - Answer -sqrt(x^(2)+x2^(2)......) propagation on uncertainty multiplication or subtraction - Answer -sqrt((x/a)^(2)+(x/b)^(2)) for gaussian curve +2 sigma is.... - Answer -68.2% for gaussian curve what is +3 sigma.... - Answer -99.7% Qcalc - Answer -(gap)/(range) Grubbs test - Answer -|mean-poss outlier|/s uncertainty - Answer -mu=mean+/- ts/SQrt(N) S pooled - Answer -sqrt((Na-1)sa^(2)+(Nb-1)sb^(2))/(Na+Nb-2) tcalc - Answer - Least sq method - Answer -The best fit line through a set of data points in which the line which min the sum of sq of deviations between data points and lines. linear range - Answer -conc range of analyte over which linear detector is linearly proportional Sensativity - Answer -slope of linear portion of a/b curve min det limit - Answer -3s/m lim of quant - Answer -10s/minternal calibration - Answer -carried out through the method of standard additions. Known analyte. method of standard additions - Answer -accounts for matrix effects. Calibration occurs within the sample matrix multi-point standard addition - Answer -4-5 id clean and dry vol flasks obtained. Volume of sample added to each flask. Next variable amounts of standard solution spiked in each flask. Requirements of Internal standard - Answer -1. Must produce a response easily distinguishable from analyte 2. Should be chemically similar