Răspuns:
1.
MCaO=40+16=56g/mol
m=n×M=3×56=168g
100gCaO........90g CaO pur
168gCaO.........xg CaO pur
x=168×90/100=151,2g CaO pur
MCa=40g/mol
2×40g............2×56g
2Ca + O2 => 2CaO
yg....................151,2g
y=151,2×2×40/2×56= calculează
2.
MFe =56g/mol
MS=32g/mol
MFeS=56+32÷88g/mol
56g.....32g.....88g
Fe + S => FeS
zg.........tg........264
z=264×56/88= calculează
t=264×32/88= calculează