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In 400 g solutie de HCl de concentratie necunoscuta se adauga 200 g
apa. Daca solutia obtinuta are concentratia 20%, sa se calculeza
concentratia procentuala masica a solutiei initiale..



Răspuns :

ms1 = 400g
m apa = 200 g
c2=20%
c1=?
c2=md2/ms2*100=>md2=600*20/100=120 g
ms2=ms1+m apa = 400+200=600 g
md2 = md1
c1=md1/ms1*100=120/400*100=30%