“Moles”

MOLE  is a way of translating between grams and amu’s a mole is a number that helps us translate between the atomic world and our every day world specifically  “6.02 x 1023” known as: “Avogadro’s Number”

MOLE  is a direct translation 1 mole of an atom’s amu = 1 g between grams and amu’s 1 mole of an atom’s amu = 1 g 1 gram = 6.02 x 1023 amu = 1 mole (e.g.) carbon-12 [12C] = 12 amu 12 amu = 6.02 x 1023 of carbon atoms 6.02 x 1023 of 12C = 12 grams 1 gram of 12C = 1 mole of 12C

Fe MOLES and GRAMS 1 mole of an atom’s amu = 1 g 1 gram = 6.02 x 1023 amu = 1 mole Fe = 55.85 = 56 amu 56 amu = [56Fe] 56 amu x 6.02 x 1023 = 1mole 1 mole of 56Fe = 56 g 26 Fe iron 55.85

Si 28 MOLES and GRAMS 1 mole of an atom’s amu = 1 g 1 gram = 6.02 x 1023 amu = 1 mole Si = 28.09 = 28 amu 28 amu = [28Si] 28 amu x 6.02 x 1023 = 1mole 1 mole of 28Si = ___ g 14 Si silicon 28.09 28

Si 56 MOLES and GRAMS 1 mole of an atom’s amu = 1 g 1 gram = 6.02 x 1023 amu = 1 mole Si = 28.09 = 28 amu 28 amu = [28Si] 28 amu x 6.02 x 1023 = 1mole 2 moles of 28Si = ___ g 14 Si silicon 28.09 56

O 64 16 MOLES and GRAMS 1 mole of an atom’s amu = 1 g 1 gram = 6.02 x 1023 amu = 1 mole O = 15.999 = ___ amu 16 amu = [16O] 16 amu x 6.02 x 1023 = _ mole 4 moles of 16O = ___ g 8 O oxygen 15.999 16 1 64

MOLAR MASS Molar Mass is measured in grams per mole (g/mol) EQUALS the MASS of “1” MOLE of a substance it is the MASS of “1” MOLE of a single TYPE OF ATOM (an element) if the substance consists of a molecule, the molar mass is the MASS of each individual atom in that molecule / compound Molar Mass is measured in grams per mole (g/mol)

Molecular Mass is measured in grams per mole (g/mol) is the combined MASS of the group of atoms forming a SINGLE MOLECULE (smallest unit of a compound) FIND by “adding” the MASSES of the atoms forming the molecule Molecular Mass is measured in grams per mole (g/mol)

GRAMS per MOLE g/mol  how the number of GRAMS of “1” MOLE of any substance would feel (e.g.) Molecular Mass of CO2 = 44 g/mol EXPLANATION: If you had “1” mole of a CO2 molecule, its mass would be 44 g (the feel of “44” USA dollar bills stacked in your hand)

MASS in AMU 12C = 1 mole = 6.02 x 1023 12C = 12 amu = 12 g/mol = 12 g you can express the MASS of an ATOM (ELEMENT) or a single molecule (COMPOUND) in AMU (atomic mass units) (e.g.) 12C = 12 amu = 1 mole 12C = 1 mole = 6.02 x 1023 12C = 12 amu = 12 g/mol = 12 g

FINDING MOLECULAR MASS: 1st  look up the Average Atomic Masses of the molecule’s component ELEMENTS on the Periodic Table 2nd  round each Average Atomic Mass to the nearest WHOLE number 3rd  use the ATOMIC MASS of each ATOM per ELEMENT in the COMPOUND 4th  find the TOTAL SUM

C O EXAMPLE – Finding Molecular Mass C = 12.01 = 12 amu in AMU: CO2 C = 12.01 = 12 amu O = 15.999 = 16 amu CO2 = 1 (C atom) + 2 (O atoms) CO2 = 1 (12 amu) + 2 (16 amu) CO2 = 12 amu + 32 amu CO2 = 44 amu 6 C carbon 12.01 8 O oxygen 15.999

CONVERTING amu to g/mol: seldom refer to MOLECULAR MASS in amu units, but rather in g/mol to convert amu to g/mol just simply change the units FROM amu TO g/mol “1” MOLE of any type of ATOM has a MASS in grams EQUAL TO the ATOM’s MASS measured in amu

C O EXAMPLE – Converting amu into C = 12.01 = 12 g/mol O = 15.999 = 16 g/mol CO2 = 1 (C atom) + 2 (O atoms) CO2 = 1 (12 g/mol) + 2 (16 g/mol) CO2 = 12 g/mol + 32 g/mol CO2 = 44 g/mol 6 C carbon 12.01 8 O oxygen 15.999

Avogadro’s Number: 6.02 x 1023 Amedeo Avogadro Italian physicist (1811) discovered that equal volumes of different gases contain equal numbers of molecules if pressure and temperature are kept constant Avogadro’s number = 6.02 x 1023 particles/mole Avogadro's number can be applied to any substance since it corresponds to the number of atoms/molecules needed to make up a mass equal to the substance's atomic or molecular mass in amu which then converts into g/mol

AVOGADRO’S NUMBER and MOLES:

HAPPY MOLE DAY Oct 23rd