|Address||P.O. Box 219 Batavia, IL 60510|
We cannot see atoms or molecules. We cannot touch them or feel them to determine their size. But we can count them! How can that be? The average atomic mass of atoms and Avogadro’s number are routinely used to count both atoms and molecules—chemists count atoms by weighing them. “Counting by weighing” makes it possible to analyze compounds found in nature and synthesize new compounds in the lab.