Question

1.masa dizolvant=50 g  sare
masa apa=350 g
c=?
2.masa apa=60 g
c=10 %
masa zahar=?
3.masa solutie=260 g
masa dizolvant=30 g
c=?
4.masa solutie=40 g
c=25%
masa apa=?
Urget!!!

Answer 1

1)c%=md/ms*100 = 50/400 * 100 = 12,5%
ms = md + m apa = 50 + 350 = 400 g
2)ms = md + m apa
c% = md/ms * 100 => 10 = md/(md + 60) * 100
=> 100md = 10 md + 600 => md = 6,666 g
3)c%=md/ms * 100 = 30/260 * 100 = 11,538%
4)c%=md/ms*100=>md = 40*25/100 = 10 g
ms = md + m apa => m apa = 40-10 = 30 g