Analytical Chemistry Final- ACS Exam 2024/2025

Analytical Chemistry Final- ACS Exam 2024 ppm - Answer -(grams analyte/grams sample)x10^6 Molarity - Answer -moles analyte/liter of solution Volume Percent - Answer -(volume solute/volume soution)x100 Volume ppm - Answer -(volume solute/volume solution)x10^6 kilo- - Answer -10^3 deci- - Answer -10^-1 centi- - Answer -10^-2 milli- - Answer -10^-3 micro- - Answer -10^-6 nano- - Answer -10^-9 pico- - Answer -10^-12 femto- - Answer -10^-15 weight percent - Answer -(grams analyte/grams sample)x100 ppt - Answer -(grams analyte/grams sample)x10^3 ppt simplified - Answer -gram analyte/liter solution ppm simplified - Answer -mg analyte/liter solution ppb simplified - Answer -micrograms analyte/liter solution pptr simplified - Answer -nanograms analyte/liter solution buoyancy correction - Answer -m=(m'(1-(air density/weight density)))/(1-(air density/object density)) accuracy - Answer -closeness of the mean to the "true value" precision - Answer -reproducibility of individual measurements Uncertainty in Addition/Subraction - Answer -e=sqrt(ex1^2+ex2^2+ex3^2+...) Uncertainty in Multiplication/Division - Answer -e=y*sqrt((ex1/x1)^2+(ex2/x2)^2+(ex3/x3)^2+...)Significant Figures in Logarithms and antilogarithms - Answer -the number of significant figures in the log should equal the number of digits in the mantissa How many significant figures in log(205.5) - Answer -four significant figures, so you will need four decimal places in your answer pH - Answer --log[H3O+] [H3O+] - Answer -10^-pH Absorbance - Answer --log(transmittance) Random Error - Answer --repeated measurements are sometimes high and sometimes low -cannot be corrected for Systematic Error - Answer --repeated measurements are usually always high or always low -can and should be corrected for Relative uncertainty= - Answer -absolute uncertainty/magnitude of measurement 68% of measurements in a Gaussian Curve will lie - Answer -between the mean-1 and the mean+1 Variance in standard deviation - Answer -standard deviation squared mean= - Answer -true value +-time*standard deviation T-test Case 1 - Answer -measure sample of known composition T-test case 2 - Answer -compare replicate measurement of an unknown sample T-test case 3 - Answer -compare individual difference of an unknown sample - two sets of data analyzed by both methods being used T-test case 1 equation - Answer -true value= mean (+-) (time*standard deviation)/sqrt(number of measurements)) T-test case 1 Tcalc= - Answer -(sqrt(n)Iknown value-calculated meanI)/standard deviation For Case 1: