3D Counting Atoms and Molecules

Atomic Mass

This video lesson focuses on the concept of atomic mass, which is the average mass of all the isotopes of an element. Listen carefully. Duration: 7:54.

Relative Masses

When we compare the masses of two objects against each other we are looking at their relative masses. A golf ball, for example, is about 20 times more massive than a ping pong ball. Likewise, we can talk about the relative masses of atoms. We get these relative masses from the periodic table. Duration: 4:29.

Measuring Masses of Reactants

This video lesson is one of the most difficult to understand video lesson in this entire series. Follow very carefully as the concept of formula mass is presented and applied to chemical reactions. Duration: 7:08.