Question

Se amesteca 200 g solutie 20 % sare cu 200 g solutie 10 % sare si 200 g apa. Ce comcentratie procentuala va avea solutia obtinuta? Ajutati-ma, va rog!

Answer 1

Solutia 1:
ms1=200g
c1=20%
⇒ $c1=\frac{md1}{ms1} *100$ ⇔ $md1=\frac{c1*ms1}{100}$=40 g

Solutia 2:
ms2=200 g
c2=10%
⇒ $c2=\frac{md2}{ms2} *100$ ⇔ $md2=\frac{c2*ms2}{100}$=20 g

concentratia finala=$\frac{md1+md2}{ms1+ms2+mH20} *100= \frac{40+20}{200+200+200}*100 = \frac{60}{600} *100=10$%