Question

Peste 300 g solutie de acid clorhidric se adauga 200 g apa. Concentratia solutiei devine 20%. Care a fost concentratia initiala a solutiei?

Answer 1

c final=(md final/ms final)*100=>md final=(c final * ms final)/100=(200+300)*20/100=100g
md final = md init
c init=(md init/ms init)*100=>c init=(100/300)*100=> c init = 33,33%

Scuze de intarziere :)