2Mg + O2 = 2МgO
V(Mg) = 12/24 = 0,5моль
V(O2)=0,25моль
m(O2) = V*M = 0,25 * 32 = 8г.
X1 - водород.
СН3-СН=СН2 + Н2 --(Ni, t°)--> CH3-CH2-CH3
S→SO₂→H₂SO₃→Na₂SO₃S+O₂=SO₂SO₂+H₂O=H₂SO₃H₂SO₃+2NaOH=Na₂SO₃+2H₂O
Ca(OH)2 + 2HCl = CaCl2 + 2H2O
Ca(+2) + 2OH(-1) + 2H(+1) + 2Cl(-1) = Ca(+2) + 2Cl(-1) + 2H2O
OH(-1) +H(+1) = H2O