Answer:
If anything but H2O were found, it would be evidence of a chemical change. Therefore, 4 is the only viable evidence that it was a physical change of H2O liquid to H2O gas.
Answer 2, because when you add salt to something, it cools faster (ex. When you add salt to an ice chest so that it stays cold) and it takes longer to boil (ex. When you boil salt out of ocean water so that its safe to drink) therefore, the more NaCl in the solution, the more it will exibit these properties
The postulate of Dalton's atomic theory which is a result of the law of conservation of mass is: Atoms are indivisible particles, which can neither be created nor destroyed in a chemical reaction.
