Question

In 150g solutie de concentratie 5℅ se adauga 100g solutie de concentratie 10℅ .Ce concentratie are solutia finala?

Answer 1

150 × 5 / 100 = 7,5g masa de substanta dizolvata in prima solutie
100 ×10 / 100 = 10g masa de substanta dizolvata in a doua solutie

cf (conc. finala) = (md1 + md2) ×100 / (ms1+ms2)
cf = 17,5 ×100/250
cf = 175/25 => cf = 7%

Answer 2

md1 = 150*5/100 = 7,5 g
md2 = 100*10/100 = 10 g
md3 = md+md2 = 10+7,5 = 17,5 g
ms3 = ms1+ms2 = 150+100 = 250 g soluție
c3 = 17,5/250*100 = 7%