MasteringChemisty Ch 0S HW Google Chrome 8 https://session.masteringchemistry.co
ID: 920756 • Letter: M
Question
MasteringChemisty Ch 0S HW Google Chrome 8 https://session.masteringchemistry.com/myct/itemView?assignmentProblemiD-50345123 ht Fal Ch.05 HWllem 15 « previous 15 of 36 next . Item 15 ardized way of reporting the optical Specific rotation sample The value is obtained by measuring tho optical activity (observed of a sample solution at a concentration c of specilic rotation of the sample is then calculated by ical activity of a given conm pound and is useful when assessing the enantiomeric purity of a ed by dividing the the measured rotation by the concentration of the sample and length of the s.ample cell path A pharmaceudical chemist is working on a new large-scale synthesis for the popular pain reliever, napeoxen To be useful, however, the synthesis for whereas the (S) isomer of naproxen is a safe pain redcing drug. the R isomer a potentialy harmful liver toxin. l must be highly stereospecific. To delermine the purity a 500-cm tube, observing a value of +1.03" A 0 560 g/m of the synthesized product, the chemist dissolves 88 4 mg of obtained product in 2 60 mli of solvent and measures the optical activity of the sample in solution of pure ( S) isomer is measured under identical conditions, giving a value of 185 You are asked to determine the percentage of (S)naproxen in the prepared product Part A Start your analysis by determining the specific rolation jol of pure (Synasgroxen using the Information giren A 0560 g/al solution of pare (S) isomer is measured in a 5.00-cn tube, giving a valus of 185 Express your answer in degrees [al-66.9 SON ts Manner GiveUp Benempati hemist Correct oe__ w@81 a-s ch the web and WindowsExplanation / Answer
Part C :
% Optical purity = [(specific rotation of enantiomeric mixture)/(specific rotation of pure enantiomer)] * 100
= (60.6/65.9)*100
= 91.96%
Part D:
Optical purity means that in the enantiomeric mixture , the excess of S-isomer is 91.96 % and remaining 8.04 % exists as racemic modification. So
% of S isomer = 91.96 + (8.04/2) = 95.98 %