Răspuns:
2H2+O2→2H2O
MH2O=2×1+16=18g/mol
18gH2O...................2gH....................16gO
100gH2O.................xgH.....................ygO
x=100×2/18=calculeaza
y=100×16/18=calculeaza
2Ca+O2→2CaO
MCaO=40+16=56g/mol
56gCaO.........................40gCa..................16gO
100gCaO.........................agCa.....................bgO
a=100×40/56=calculeaza
b=100×16/56=calculeaza
Explicație: