Question

1 .Se adauga 2000 g apa peste 5000 g solutie de concentrație 40% . Aflati concentratia procentuala a solutiei obtinute. .
2 .Din 800 g solutie de concentrație 20% se evaporă 200 g apa . Aflati concentratia procentuala a solutiei obtinute. ....
Va rog ajutat- ma !!!

Answer 1

1.

ms1=5000g

c1=40%

c=mdx100/ms--->md1=  2000g

ms2= ms1+m,apa=7000g

md2=md1

c2= 2000x100/7000 g=..................calculeaza !!!!   c2 va fi <c1 ...solutia se dilueaza

2.  

ms1=800g

c1= 20%

md1= c1xms1/100= 160g

ms2=ms1-m,apa= 600g

c2= 160x100/600=....................calculeaza !!!!     c2 va fi > c1 ...solutia se concentreaza