Question

ce cantitate de zahar trebuie adaugata in 95g solutie de concentratie 10% pentru a se obtine o solutie de concentratie de 20%?

Answer 1

ms₁=95 g
c₁=10%
c₂=20%
c₁=md₁·100/ms₁
=> md₁=95·10/100
=> md₁=9,5 g zahar initial
ms₁=md1+mH₂O
=> mH₂O=95-9,5
=> mH₂O=85,5

md₂=ms₁-mH₂O

md₂=c₂*(md₂+mH₂O)/100
100md₂=20md₂+20·85,5
80md₂=1710
=> md₂=21,37 zahar
21,37-9,5=11,87 zahar adaugat