Question

intr-un vas cu apa se dizolva 360 g substanta obtinandu-se o solutie de c=25%.Cata apa s-a folosit? SI O solutie de concentratie 25% contine 1200 g apa.Cata substanta dizolvata contine solutia? Va rog cat mai repede.Multumesc.

Answer 1

md=360g

c=25%

c=mdx100/ms---> ms= mdx100/c= 1440g

dar ms= md+m,apa---> mapa= 1440-360=....................calculeaza !!!

c=25%

m,apa=1200g

c=mdx100/ms,          unde ms=md+m,apa

25= mdx100/(md+1200)

100md= 25md+ 30000------> calculeaza md !