To demonstrate that matter is conserved during a chemical change or reaction, the best procedure from the options provided is the one involving the mass of an acid and a base:
Find the mass of an acid and a base. Combine them to produce water and a salt. Find the mass of the water and salt.
Rationale:
- Chemical Reaction: The reaction between an acid and a base is a chemical change that produces water and a salt. This is a clear example of a chemical reaction.
- Measurement of Mass: By measuring the total mass of the reactants (acid and base) before the reaction and then measuring the total mass of the products (water and salt) after the reaction, you can demonstrate that the total mass remains the same, thereby demonstrating the conservation of mass.
- Closed System: It is crucial that the reaction occurs in a closed system to prevent the loss of any gases (which can occur in some reactions) or any other materials during the process.
Other Options:
- Tearing paper: This shows physical change, not a chemical change, and does not demonstrate conservation of mass effectively.
- Melting butter: This is also a physical change, not a chemical one, so it does not illustrate the conservation of mass in a chemical reaction.
- Burning a log: While this does demonstrate a chemical change (combustion), measuring just the ash will not account for the gases (like carbon dioxide and water vapor) that are released during burning, making it difficult to accurately demonstrate conservation of mass without a closed system.
In summary, using the acid and base reaction provides the clearest and most effective demonstration of conservation of mass during a chemical change.
1 answer