After a reaction in an open container, the measured mass appears lower because a gas produced has escaped. What is the correct scientific explanation?
Answer and explanation
Correct answer: The mass of the escaped gas was no longer included in the system being measured
The law of conservation of mass applies when the complete system is considered. In an open container, a gaseous product can leave before weighing, so the measured system contains less material and its apparent mass decreases. The gas has not been destroyed; it is simply outside the chosen system boundary. The reaction may still be chemical and has produced a product. Hence option B is correct.
Frequently asked questions
What is the correct answer to this question?
The mass of the escaped gas was no longer included in the system being measured
Why is this the correct answer?
The law of conservation of mass applies when the complete system is considered. In an open container, a gaseous product can leave before weighing, so the measured system contains less material and its apparent mass decreases. The gas has not been destroyed; it is simply outside the chosen system boundary. The reaction may still be chemical and has produced a product. Hence option B is correct.
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.
