Question

3g de soda caustica se dizolva in apa si se formeaza o solutie de concentratie 2%.Ce masa de apa a fost necesara?

Answer 1

c=md/ms ·100
ms=md+mH2O
2=3/(3+mH2O)  · 100⇒  300=6+2·mH2O  ⇒  294=2·mH2O
mH2O = 148 g

Answer 2

md=3 g
C%=2%
m apa =?
c=md/ms*100 rezulta ms=md*100/C=3*100/2=300/2=150 g solutie
m apa= ms-md=150-3=147 g H20