A chemical reaction is done in the setup shown, resulting in a change of mass. What will happen if the same reaction is done in a sealed container that is placed on the electronic balance?

Correct Answer: B. The mass will stay the same because the gases produced in the reaction are kept inside the container.

Explanation: The law of conservation of matter states that, in any physical or chemical process, matter is neither created nor destroyed. Because the amount of matter does not change, the mass must remain the same.

The reason the mass decreases in the original reaction is that one of the products of the reaction is a gas, which floats away into the surrounding air. Because the mass of the gas is removed, the mass on the scale goes down. In a closed container, the gas produced in the reaction will not escape, so the total mass inside the container does not change.

The mass of the system will remain the same if there is no conversion of mass to energy in the reaction.

Explanation: If the system is closed, then according to the law of mass conservation the mass of the reaction system will remain the same. Law of conservation of the mass: In simple words, it is described as the mass of a closed system can never be changed, it may transfer from one form to another or change into energy. But if the reaction involves energy transfer like heat or light production, in this case, the mass can be changed.