Explicație:
a) MCa(OH)2=40+2×16+2×1=74g/mol
74gCa(OH)2.............40gCa
xgCa(OH)2................80gCa
x=80×74/40=148g
b) 74gCa(OH)2..............32gO
ygCa(OH)2.......................64gO
y=64×74/32=148g
