Urgent
Dau coroana.....................

Răspuns:
MCaO=40+16=56g/mol
MO2=2x16=32g/mol
32g..........2x56g
2Ca + O2 → 2CaO
32g.........xg
x=32x2x56/32=112g CaO
calculam in moli
n=m/M=32/32=1mol O
1mol.....2moli
2Ca + O2 → 2CaO
1mol.....ymoli
y=1x2/1=2moli CaO
Explicație: