Answer:
Boil the water and stir in potassium nitrate. If it doesn't all dissolve, you can cook it on the stove or microwave it until the water boils again. Remove the solution from heat, but let it cool slowly for the best crystal formation.
Answer:
I don't know if you can directly prove it with evidence if you haven't observed it but you can maybe take an educated guess by the aftermath of it?
For example, you see a burnt log. At this time, people don't know what fire is. After we study the log, we could see that it takes extreme temperature in order to burn the log and that would help people see that there is a force like fire that can cause this. In a way, finding out that extreme temperatures burns stuff is another step closer to the discovery and proof of fire
I hope that makes sense
I think the answer will be 60 and the reason why is because
Catalyst increases the rate of a chemical reaction