Question

a sample of ammonium nitrate (a white solid) is placed in an erlenmeyer flask and closed with a rubber balloon. the setup is weighed. the flask is gently heated and the balloon inflates as seen. the flask is then placed in ice water where the balloon deflates and water condenses on the inside walls of the flask. the ammonium nitrate dissolves in the water. the setup is weighed again and has not changed. select the correct observation and conclusion. a the mass does not change, so it must be a physical process. b the ammonium nitrate dissolves, which is a chemical process. c the balloon only inflates due to thermal expansion, a physical process. d the condensed water is a new substance, the result of a chemical process.

Explanation:

1. A physical process is one where no new substances are formed and mass is conserved in both physical and chemical processes according to the law of conservation of mass, so option A is incorrect.
2. Dissolving ammonium nitrate is a physical - change as it is just the separation of ions in solution without forming new substances, so option B is incorrect.
3. When the flask is heated, the air inside expands causing the balloon to inflate. This is a physical process due to thermal expansion of air.
4. The condensed water is just water that has changed state from vapor to liquid, not a new substance formed by a chemical reaction, so option D is incorrect.

Answer:

C. The balloon only inflates due to thermal expansion, a physical process