Explain why seeing a gas doesn not always indicate that there was a chemical change. ​

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

because of all the things that happen around the us, many people get into arguments which sadly could get physical, but we should actually make a change for that.