Final answer:
In the vinegar-baking soda reaction, the mass of products was equal to the mass of reactants, in accordance with the law of conservation of mass. Even outside the laboratory, mass must be conserved in a closed system during chemical reactions. The correct option is C.
Step-by-step explanation:
In trial 1 of the vinegar-baking soda reaction, the mass of the products was equal to the mass of the reactants. This observation supports the law of conservation of mass which states that during a chemical reaction, mass is neither created nor destroyed. Therefore, when we compare the mass of reactants to the mass of products, they should remain constant if the system is closed and there is no loss of mass to the surroundings.
For example, when bread dough is baked, the mass of the baked loaf is less than the one pound of original dough because gases are released during baking. However, if we could capture all the gases and include them, the total mass would be conserved. Similar principles apply to the burning of magnesium, where the mass of magnesium oxide produced is greater than the original piece of magnesium, because oxygen from the air has combined with the magnesium. For the sealed flask experiment by Lavoisier, the mass of the sealed flask and contents would remain the same after heating, demonstrating the conservation of mass.