Atoms and Moles

ATOMS AND MOLES

The foundation of chemistry and how it all began...

Atoms

1. All mater is composed of atoms 2. There are a limited # of different types of atoms; each type of atom is an atom of a different element 3. A large number of atoms of a single element always has the same average mass4. Atoms combine to form compounds5. A pure compound always has the same whole-number ratio of different atoms (water is always H2O) 6. If the whole-number ratio of the atoms (and, therefore, the ratio of the masses) changes then a new compound has been formed. For example, H2O2 is not water

Empirical Formula and Mass %

Empirical formula from mass composition | Chemistry | Khan Academy (Embed)

Caption: : Khan Academy- Empirical Formula

Percent Composition By Mass (Embed)

Caption: : Percent Composition by Mass

Molecular Formula

Calculating Molecular Formula from Empirical Formula (Embed)

Caption: : Molecular Formula given Empirical Formula or Mass %

Moles

Avogadro's number- the number of particles in one mole Average atomic mass is in amuKnowing the number of moles is vital to many later equations in chemistry If you can't do the stoich...convert it to moles!

Introduction to Moles (Embed)

Caption: : A brief video offering food comparisons to moles