Describe the graph of the cooling curve of water (in terms of time heat is added vs temperature) PLEASEEE HELP

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?

What properties would have caused early researchers to name hydrogen "inflammable air”

Explaining why atoms bondcomplete the sentence.atoms form chemical bonds to satisfy the    rule and to become  .