The look and feel of a rocks surface is its what

Describe the properties of sodium, chlorine, and sodium chloride

Which is true according to the law of conservation of energy

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?