Question

Before burning, the initial mass of a candle is 9.5 grams. After burning for several minutes, the final mass is 5.4 grams.

Which of the following is the best explanation for the measured masses before and after the chemical reaction?

A. The mass in the wax candle transforms into energy that is burned, hence the higher mass after the reaction.

B. The mass in the wax candle transforms into a gas that is released when burned, hence the lower mass after the reaction.

C. This cannot be an accurate measure of the final mass because the reactants and products should be equal according to the law of conservation of mass.

D. This cannot be an accurate measure of the final mass because the products should always have a greater mass than the reactants according to the law of conservation of mass.

Answer 1

The correct answer is B.

Step-by-step explanation:

The mass in the wax candle transforms into a gas that is released when burned, hence the lower mass after the reaction.

Burning a candle involves a chemical reaction in which the wax in the candle reacts with oxygen in the air to produce carbon dioxide and water vapor. During this reaction, some of the wax is transformed into a gas, which is released into the air. This means that the total mass of the reactants (wax and oxygen) is greater than the total mass of the products (carbon dioxide, water vapor, and unreacted oxygen), resulting in a lower mass after the reaction.

This is consistent with the Law of Conservation of Mass, which states that the total mass of the reactants is equal to the total mass of the products in a chemical reaction. However, it is important to note that in this case, the mass loss is due to the release of gas, rather than a violation of the law of conservation of mass.