Question

1. in a student - designed experiment to investigate mass conservation in a reaction, they choose to decompose hydrogen peroxide into water and oxygen. to prove comprehensive evidence for mass conservation, what combination of steps should the students include in their experimental design? measuring only the mass of hydrogen peroxide before the reaction and the water after the reaction. measuring the initial mass of hydrogen peroxide and the mass of water and oxygen separately after the reaction. capturing and measuring the oxygen gas produced while counting the mass of water formed. measuring the initial and final mass of the system in a closed container, including all reactants and products.

Explanation:

To prove mass conservation in a chemical reaction, one must measure the total mass before and after the reaction in a closed - system to account for all reactants and products. Measuring only some components won't give a full picture. Measuring the initial and final mass of the system in a closed container (including all reactants and products) ensures that no mass is lost or gained from the outside environment, which is key to demonstrating mass conservation.

Answer:

Measuring the initial and final mass of the system in a closed container, including all reactants and products.