Question

Ce concentratie procentuala are solutia obtinuta in final prin adaugarea a 100 g apa peste 200 g solutie de sare de bucatarie avand concentratia de 15%?

Answer 1

Calculez masa de sare dizolvata in solutia initiala cu formula: c/100= md/ms => md = c*ms/100=15*200/100=30 g. Masa de solutie dupa adaugarea apei devine 200+100=300 g. Cum apa nu modifica cantitatea de sare, md ramane la fel. cf/100= md/msf => cf=md*100/msf => cf=15*100/300=5%