Question

HELP WITH THIS WORD PROBLEMStudents want to gather evidence for the claim that the number of atoms present before a chemical reaction is equal to the number of atoms present after the chemical reaction. They decide to react vinegar and baking soda in a sealed plastic bag. Which of the following would provide the evidence the students need?

The mass of the plastic bag, baking soda, and vinegar before the reaction was equal to the mass after the reaction.
Bubbles were produced during the reaction, which meant that a gas was being produced
.The plastic bag did not change in any way, indicating that it was not involved in the reaction.
The mass of the baking soda was exactly equal to the mass of the vinegar used to create the chemical reaction.

Answer 1

The best evidence for the law of conservation of mass during the vinegar and baking soda reaction is to measure and show that the mass before and after the reaction in a sealed bag is the same, as this indicates no atoms are gained or lost.

Step-by-step explanation:

When vinegar reacts with baking soda in a sealed plastic bag, three possible observations to test the law of conservation of matter are considered. The best evidence to prove that the number of atoms remains constant during this chemical reaction would be to measure the mass before and after the reaction. If the mass of the plastic bag, baking soda, and vinegar before the reaction is equal to the mass after the reaction, it provides strong evidence that the law of conservation of mass holds true because mass is conserved in a closed system. Bubbles or other physical changes do not provide direct evidence of conservation of mass, and the equal masses of individual reactants do not alone confirm that the overall mass is conserved. The correct approach is to demonstrate that the total mass, which corresponds to the number of atoms present, neither increases nor decreases during the reaction.

To provide additional support, one could also balance the chemical equation of the reaction between vinegar (acetic acid) and baking soda (sodium bicarbonate), ensuring that the number of atoms for each element is the same on both sides of the equation. This is called stoichiometry, and it is a way to quantify the exact amounts of substances involved in a reaction and thereby uphold the law of conservation of mass.