M,acid salicilic= 138g/mol
M,acid acetilsalicilic= 180g/mol
n, acid salicilic= 552g/138g/mol= 4mol
1mol............................................................1mol
C6H4(OH)COOH + CH3COCL---> C6H4(OCOCH3)-COOH +HCL
4mol..............................................................x=4mol
mteor=nxM= 4molx180g/mol= 720g acid acetil salicilic
95/100= m,pr/m,teor---> m,practic= 95x720/100g= 684g