Question

1.Determinati cate grame de apa si sare se afla in 250 de grame de solutie cu concentratia de 6%. 2.Se amesteca 20 grame sare cu 260 grame apa.Aflati concentratia!

Answer 1

1.c=md/ms *100
c-concentratie
md-masa dizovatului
ms-masa solutiei
6=md/250*100
md/250=6/100
md*100=250*6
md=250*6/100
md=5*6/2
md=15 g sare
mH2O=250-15=235g H2O

2. ms=260+20= 280 g solutie
c=20/280*100
c=1/14*100
c=7,14%