Question

Va rog la 1 si la 3 !!!! am nevoie urgent INTREBARE DE 34DE PUNCTE

Answer 1

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: