Question

150 g de sirop , c=10% , se dizolva zahar pana ce concentratia se dubleaza . Calculati masa de zahar adaugata.

Answer 1

md1 = c1 x ms1 / 100 = 10 x 150 / 100 = 15 g zahar initial
Notam cu x = m zahar adaugat
c2 = 20% (dublul conc initiale, de 10%)
c2 = md2 x 100 / ms2
md2 = md1 + x = 15 + x
ms2 = ms1 + x = 150 + x
20 = (15+x) x 100 / 150 + x ⇒ x = 18,75 g zahar adaugat.