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 mass
• 4. Atoms combine to form compounds
• 5. 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 (Einbetten)
• Bildunterschrift: Khan Academy- Empirical Formula
• Percent Composition By Mass (Einbetten)
• Bildunterschrift: Percent Composition by Mass

Molecular Formula

• Calculating Molecular Formula from Empirical Formula (Einbetten)
• Bildunterschrift: Molecular Formula given Empirical Formula or Mass %

Moles

• Avogadro's number- the number of particles in one mole
• Average atomic mass is in amu
• Knowing 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 (Einbetten)
• Bildunterschrift: A brief video offering food comparisons to moles