During an unknown process in a closed container, the properties of a substance changed, a new substance was formed, and the total mass remained unchanged. What is the most appropriate conclusion?
Answer and explanation
Correct answer: A chemical reaction occurred, and the law of conservation of mass was demonstrated.
Formation of a new substance and a change in chemical properties identify a chemical reaction rather than a merely physical change. Because the container is closed, no reactant or product can escape, so the total mass before and after the reaction remains equal. This demonstrates conservation of mass. Option A combines both conclusions; option B ignores the new substance, while C and D contradict the evidence.
Frequently asked questions
What is the correct answer to this question?
A chemical reaction occurred, and the law of conservation of mass was demonstrated.
Why is this the correct answer?
Formation of a new substance and a change in chemical properties identify a chemical reaction rather than a merely physical change. Because the container is closed, no reactant or product can escape, so the total mass before and after the reaction remains equal. This demonstrates conservation of mass. Option A combines both conclusions; option B ignores the new substance, while C and D contradict the evidence.
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.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
