In a closed container a metal reacts with acid and gas forms but does not escape. What is the most suitable conclusion about total mass?
Answer and explanation
Correct answer: Total mass will remain same
The law of conservation of mass states that matter is neither created nor destroyed during a chemical reaction. In a closed container, the hydrogen or other gas produced by the metal–acid reaction remains inside the system, so it is included in the final measurement. Although the substances change into new products, the combined mass of all reactants and products remains constant. Hence option A is correct; an apparent decrease would occur only if gas escaped from an open system.
Frequently asked questions
What is the correct answer to this question?
Total mass will remain same
Why is this the correct answer?
The law of conservation of mass states that matter is neither created nor destroyed during a chemical reaction. In a closed container, the hydrogen or other gas produced by the metal–acid reaction remains inside the system, so it is included in the final measurement. Although the substances change into new products, the combined mass of all reactants and products remains constant. Hence option A is correct; an apparent decrease would occur only if gas escaped from an open system.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
