Răspuns:
md=250g
c= 25%
c=mdx100/ms---> ms= 250x100/25g=1000g
ms=md+m,apa---->m,apa=1000g-250g=750g
c% scade-solutia se dilueaza
ms1=200g
c1=25%
md1= c1xms1/`100= 25x200/100g=50g sare
c2=30% solutia sconcentreaza prin evaporarea solventului
md2=md1
ms2= md2x100/c2= 50x100/30g=166,7 g
m,apa evaporata= ms1-ms2= 200g-166,7g=33,3g
Explicație:
