-calculez masa de acid din solutie
c=mdx100/ms--> md= cxms/100= 21,6g HCl
-calculez moli de acid, stiind, M=36,5g/mol
n=m/M= 21,6g/36,5 g/mol=0,5917mol HCl
-din ecuatie, deduc moli CaO
1mol........2mol
CaO + 2HCl---> CaCl2 + H2O
x..........0,5917
x=n= 0,296mol CaO