1mol.......2mol.............1mol
Ca + 2H2O-------> Ca(OH)2 + H2
40g.........2x18g............74g
2g...........x= 1.8g ..........y=3,7g
solutia este formata dIn 3,7g Ca(OH)2 dizolvat in restul de apa (20-1,8)ce ramane dupa desfasurarea reactiei
c= mdx100/ms , unde ms= md+m,apa= 3,7+18,2=> 21,9g
c= 3,7x100/ 21,9=....................calculeaza !!!!