Atomic Mass is the Mass of One Mole of an Element One mole of chlorine is Avogadro’s number of chlorine atoms: 602,000,000,000,000,000,000,000 chlorine atoms, or better yet, 6.02 x 1023 chlorine atoms One mole of chlorine has a mass of 35.45 grams 20 30 10 40 50

Molecular Mass is the Mass of One Mole of a Molecular Compound One mole of carbon tetrachloride is Avogadro’s number of CCl4 molecules 12.01 g/mol: Atomic mass of carbon 35.45 g/mol: Atomic mass of chlorine 1 x 12.01 = 12.01 + 4 x 35.45 = 141.81 Molecular mass of CCl4: 153.82 g/mol CCl4

Formula Mass is the Mass of One Mole of the Chemical Formula of a Compound One mole of sodium chloride is Avogadro’s number of NaCl formula units. Salt is a crystal. NaCl does not form a molecule made of one Na and one Cl. 22.99 g/mol: Atomic mass of Na + 35.45 g/mol: Atomic mass of Cl 58.44 g/mol: Formula mass of NaCl NaCl crystal

Molar Mass is the Mass of One Mole of: Cl An element A molecular compound An ionic compound formula CCl4 NaCl

Conversions Transfer Through the Mole Volume of gas at STP in liters Use 22.4 Mass in grams Use Molar Mass in L mole grams mole moles Particles (Atoms, Molecules or Formula Units) Use Avogadro’s Number: 6.02 x 1023 particles mole