Someone me with these chemistry problems. look at the picture

What must be in balance for temperatures to remain constant?

Awhite powder is added to a solution. the images show observations made before the powder is added, just after the powder has been added, and a little while later. (the liquid in the small beaker is phenol red solution.) what evidence shows that a chemical change has taken place?

Scuba divers use tanks of compressed air to them breathe. gases can be compressed because?