-calculez masa de acid din solutie
c=mdx100/ms----> md= 12,6x500/100g=63gHNO3
M,HNO3= 63g/mol-----> niu= m/M= 1MOL
-CALCULEZ moli si masa de Ca(OH)2 din ecuatia
2mol................1mol
2HNO3 + Ca(OH)2------->Ca(NO3)2 + 2H2O
1mol..................x=0,5mol
m= niuxM=0,5molx(40gCa +2x1gH+2x16gO)/mol=..........................calculeaza !!!!.