Question

2: Indicati cantitatea de sare care trebuie adaugata la 400g solutie de concentratie= 15% pentru a o concentra la 40%

Answer 1

c1 = md1/ms1 * 100
md1 = 400*15/100 = 60 g sare
md2 = md1 +x
ms2 = ms1 + x
c2 = md2/ms2 * 100
40 = 60+x/400+x * 100
6000+100x = 16000+40x
10000 = 60x
x = 166,666 g sare