9)
md1 = 500*20/100 = 100 g soda
md2 = 300*50/100 = 150 g soda
md3 = md1 + md2 = 100+150 = 250 g soda
ms3 = ms1 + ms2 + m apa = 500+300+200 = 1000 g solutie
c3 = md3/ms3 * 100 = 250/1000 * 100 = 25%
10)
ro = ms/V => ms = ro*V = 500*1,18 = 590 g solutie HCl
c = md/ms * 100 => md = ms*c/100 = 177 g HCl pur
