Răspuns:
c= mdx100/ms, unde ms= md+m,apa
a.
md=100g
m,apa=500g
ms= 600g
c=100x100/600%=16,7%
b.
rezulta o solutie c3=md3x100/ms unde md3=md1+md2 H2SO4
ms3=ms1+ms2+m,apa==600g
md1= c1xms1/100= 300x40/100g= 120g
md2= 200x70/100g= 140g
md3=260g
c3= 260x100/600%=43,3%
Explicație: