3 x 500 mg = 1500 mg = 1,5 g acid acetilsalicilic
1,5 g m g
HOOC-C6H4-OCOCH3 + H2O --H+--> HOOC-C6H4-OH + HOOCCH3
180 138
=> m = 138x1,5/180 = 1,15 g ac. salicilic la 100% dar noi avem 95%
=>
100% ........................... 1,15 g
95% .............................. n = 1,0925 g