Is it true that the overall charge of a formula unit for a compound is never zero?

How have the greenhouse gasses increased from the year 2000 to 2018

How can the periodic table be used to predict the behavior of elements?

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?