-M,MG= 24g/mol, M,MgO= 40g/mol, M,O2= 32g/mol
ecuatia reactiei chimice
2mol.........1mol............2mol sau in grame
2Mg + O2----> 2MgO
2x24g........32g..........2x40g
x.................y.................1,2g
a) x= 0,72g Mg
b) niu=m/M= 0,72/24 mol= 0,030molMg
c) y=0,48gO2
niu= m/M= 0,48/32 mol=..........................calculeaza !!!!!