Question

1. the wax seems to disappear as a candle burns. how can the law of conservation of mass apply to this reaction?

Explanation:

When a candle burns, the wax (a hydrocarbon) reacts with oxygen from the air. The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. The wax and oxygen react to form carbon dioxide gas and water vapor (which may be invisible as steam or condense as liquid water). The total mass of the wax and the oxygen consumed equals the total mass of the carbon dioxide and water produced. Even though the wax seems to disappear (as the products are often gaseous and disperse), the mass is conserved because the mass of reactants (wax + O₂) = mass of products (CO₂ + H₂O).

Answer:

When a candle burns, wax (a hydrocarbon) reacts with oxygen (\(O_2\)) from the air. By the law of conservation of mass, the total mass of reactants (wax + \(O_2\)) equals the total mass of products (carbon dioxide (\(CO_2\)) + water (\(H_2O\))). The wax seems to "disappear" because the products (\(CO_2\) is a gas, \(H_2O\) may be vapor/liquid) disperse, but their combined mass (plus the mass of consumed \(O_2\)) equals the initial mass of the wax.