Răspuns:
c= mdx100/ms
c1=30%----> md1= c1xms1/100=0,30ms1
c2=5% md2=md1
ms2= ms1+m,apa
5/100= 0,30ms1/(ms1+m,apa)
30ms1= 5ms1+5m,apa
25ms1= 5m,apa
ms1/m,apa= 1/5
daca ai de preparat noua solutie ,pui 1parte sol.30% si 5parti apa
de ex. 50g sol.30% si 250g apa
Explicație: