16. A chemist is studying the byproducts produced during the burning of gasoline. Gasoline burns by reacting with oxygen to produce water vapor and carbon dioxide. The chemist carefully measures the masses of all the substances involved in this reaction. Which observation would lead the chemist to conclude that the law of conservation of matter is obeyed in this reaction?
Answer: A
The mass of gasoline and oxygen is equal to the mass of water vapor and carbon dioxide.
The observation that the mass of gasoline and oxygen is equal to the mass of water vapor and carbon dioxide supports the law of conservation of matter, which states that matter cannot be created or destroyed in a chemical reaction. This balance in mass indicates that all reactants are accounted for in the products.
A) The mass of gasoline and oxygen is equal to the mass of water vapor and carbon dioxide.
This statement directly aligns with the law of conservation of matter, which asserts that the total mass before a reaction must equal the total mass after the reaction. By observing that the combined mass of the reactants (gasoline and oxygen) equals the combined mass of the products (water vapor and carbon dioxide), the chemist can confirm that matter is conserved during the combustion process.
B) The mass of gasoline is equal to the mass of carbon dioxide.
This statement does not provide a complete picture necessary to support the law of conservation of matter. While it may suggest a relationship between gasoline and one of the products, it ignores the mass of oxygen consumed and the other product, water vapor. Therefore, it cannot validate the conservation principle as it does not account for all reactants and products.
C) The mass of oxygen is equal to the mass of water vapor.
This observation focuses solely on the relationship between one reactant (oxygen) and one product (water vapor), which is insufficient for verifying the law of conservation of matter. It fails to consider the mass of gasoline and the other product, carbon dioxide, making it an incomplete assessment of the overall reaction.
D) The mass of gasoline and carbon dioxide is the same as the mass of oxygen and water vapor.
While this option seems to approach the concept of conservation of mass, it incorrectly combines the products with one of the reactants. The correct observation should compare the total mass of both reactants together against the total mass of both products, rather than mixing them. Thus, it does not accurately demonstrate the preservation of mass during the reaction.
Conclusion
Option A is definitively correct as it encapsulates the law of conservation of matter by ensuring that all reactant masses are accounted for in the product masses. The other options fail to satisfy this requirement, either by omitting crucial components of the reaction or by making incorrect comparisons. Therefore, only Option A adequately illustrates that matter is conserved in the combustion of gasoline.