According to the microscopic schematic diagram of the reaction, the reactants are ethylene and oxygen, and the products are carbon dioxide and water. The reaction equation is C2H4+3O2? Light it? . ? 2 CO2+2H2O；

(1) The chemical formula of the simple substance in this reaction is O2;

(2) The reaction equation is C2H4+3O2? Light it? . ? 2 CO2+2H2O； The mass ratio of the two reactants is (12× 2+14): 3×16× 2 = 28: 96.

Answer:

( 1)O2

(2)C2H4+3O2？ Light it? . ? 2CO2+2H2O 28:96