Question

A student investigated the law of conservation of mass. The law of conservation of mass states that the mass of the products is equal to the mass of the reactants.

This is the method used.
1. Pour sodium carbonate solution into a beaker labelled A.
2. Pour hydrochloric acid into a beaker labelled B.
3. Measure the mass of both beakers and contents.
4. Pour the solution from beaker B into beaker A
5. Measure the mass of both beakers and contents again.
When sodium carbonate solution and hydrochloric acid are mixed, a reaction takes place.
A student tests the law of conservation of mass using the same method. This is the equation for
the reaction.
Na:CO(aq) + 2HCI(aq) → 2NaCI(aq) + CO(g) + H2O(I)
Explain why this student's results would not appear to support the law of conservation of mass.

Answer 1

The student's experiment would not appear to support the law of conservation of mass because the production of carbon dioxide gas, which escapes into the air, is not measured after the reaction, causing an apparent loss in mass.

Step-by-step explanation:

The law of conservation of mass states that the total mass of the reactants should be equal to the total mass of the products in any chemical reaction. However, in the experiment described, the student would likely find that the mass decreases after mixing sodium carbonate solution and hydrochloric acid.

The chemical reaction given by Na2CO3(aq) + 2HCl(aq) → 2NaCl(aq) + CO2(g) + H2O(l) produces carbon dioxide gas (CO2), which escapes from the solution into the air. Since the gas is not contained, it is not accounted for in the mass measured after the reaction, leading to an apparent loss in mass.

This discrepancy does not disprove the law of conservation of mass; instead, it highlights the importance of considering all products, including gases, when conducting experiments to validate this law. For a more accurate investigation, one would need to conduct the reaction in a closed system where gases cannot escape, therefore ensuring that the total mass is conserved and measurements reflect this principle accurately.