Why is the synthesis stage called this

Which of the following is a physical property flammability heat of combustion solubility and toxicity

Which fossil fuel is mainly used for heating and cooking? a. electricity b. coal c. petroleum d. natural gas

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?