3 Which chemical equation below is balanced to correctly represent the Law of
Conservation of Mass?
04 Al + 3O2 + 2 Al2O3
O2 AL + O2 + 2 Al2O3
O AL + O2 + Al2O3

4Al + 3O₂ →   2Al₂O₃

Explanation:

    4Al + 3O₂ →   2Al₂O₃

Only this reaction above obeys the law of conservation of mass. The others flout the rule.

The law of conservation of mass states that "matter is neither created nor destroyed in a chemical reaction but are simply transformed from one form to another".

By this law, the number of atoms on both sides of expression must be the same;

                                                    Number of atoms

Elements              Left hand side                                 Right hand side

  Al                                    4                                                     4

  O                                    6                                                    6

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa