47. How is mass affected in this reaction, according to the law of conservation of matter?
Answer: A
The mass of water must equal the total mass of hydrogen and oxygen.
According to the law of conservation of matter, the total mass in a closed system must remain constant. Thus, the mass of the products, in this case water, must equal the total mass of the reactants, which are hydrogen and oxygen.
A) The mass of water must equal the total mass of hydrogen and oxygen.
This statement accurately reflects the law of conservation of matter, which states that matter cannot be created or destroyed in a chemical reaction. Therefore, the mass of the water produced must be equal to the combined mass of the hydrogen and oxygen that reacted.
B) The mass of hydrogen must equal the total mass of water.
This option is incorrect because it suggests that the mass of only the hydrogen should match the mass of the water produced, ignoring the contribution of oxygen. The total mass of both reactants (hydrogen and oxygen) must equal the mass of the product (water), not just the hydrogen alone.
C) The mass of hydrogen must equal the total mass of oxygen.
This statement is incorrect as it incorrectly equates the masses of hydrogen and oxygen without considering their actual contributions to the formation of water. The law of conservation of matter does not imply that the masses of individual reactants must be equal, but rather that their total mass combined must equal the mass of the product.
D) The mass of oxygen must equal the total mass of water.
This choice is also incorrect. While the mass of oxygen is part of the total mass that contributes to the mass of water produced, it does not account for the mass of hydrogen. Thus, the mass of oxygen alone cannot equal the mass of the water formed in the reaction.
Conclusion
Option A is the only correct answer as it embodies the principle of conservation of mass, indicating that the mass of the products (water) must equal the mass of the reactants (hydrogen and oxygen). All other options misinterpret this fundamental principle by either isolating individual components or failing to account for the complete mass balance required in a chemical reaction.