2Na + S --> Na₂S
masa Na = 46 g
=> masa Sulf care reactioneaza = (46*32) / (2 * 23) = 32 g
=> masa S ramasa = 160g- 32 g = 128g
S + O₂ --> SO₂
M(O2) = 2* 16 = 32g/mol
=> masa de O2 = (32*128) / 32 = 128 g
