Question

Se amesteca 40 g alcool pur cu 260 g solutie cu alcool de concentratie 40% Ce concentratie procentuala va avea solutia finala?

Answer 1

solutia initiala de alcool : msi = 260g  ci = 40%⇒ mdi = 104g
solutia finala : msf = 260 + 40 = 300g   mdf = 104 + 40 = 144g ⇒
⇒  c = 144·100/300 = 48%

Answer 2

c = md*100/ms
md = c*ms/100
md1 = 260*40/100 = 104 g alcool
md2 = md1 + 40 = 104+40 = 144 g alcool
ms2 = ms1 + 40 = 260+40 = 300 g apă
c2 = md2*100/ms2
c2 = 144*100/300 = 48%