intrebarea 1
md= 6,3 g , m.apa = 9,45 g
=> ms = 6,3+9,45 = 15,75 g sol. HNO3
=> ultima varianta corecta
intrebarea 2
ms1 = ? g , c1 = 80% , md1= 50g
=> ms1 = md1x100/c1
= 50x100/80 = 62,5 g
m.apa.sol.1 = 62,5-50 = 12,5 g
m.apa.adugata = ? g
ms2= 60g c2 = 10%
c% = mdx100/ms
=> md2 = ms2xc2/100 = 60x10/100 = 6 g
m.apa.sol.2 = ms2-md2 = 60-6 = 54 g
=> varianta 2 vorecta