-calculez moli si masa hidroxid , din ecuatia chimica
2mol...........1mol
2NaOH + CuSO4----> Cu(OH)2 + Na2SO4
x...................5mol
x=n= 10mol NaOH
m=nxM= 10molx(23gNa+1gH+16gO)/mol= 400g----> este masa dizolvata in solutia data=md
- calculez masa de solutie care contine md
c=mdx100/ms
2=400x100./ms-----------------------> calculeaza ms !!!!