3. “Moles”

4. 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 10 23” known as: “Avogadro’s Number”

5. MOLE  is a direct translation between grams and amu’s 1 mole of an atom’s amu = 1 g 1 gram = 6.02 x 10 23 amu = 1 mole (e.g.) carbon-12 [ 12 C] = 12 amu 12 amu = 6.02 x 10 23 of carbon atoms 6.02 x 10 23 of 12 C = 12 grams 1 gram of 12 C = 1 mole of 12 C

6. MOLES and GRAMS 1 mole of an atom’s amu = 1 g 1 gram = 6.02 x 10 23 amu = 1 mole Fe = 55.86 = 56 amu 56 amu = [ 56 Fe] 56 amu x 6.02 x 10 23 = 1mole 1 mole of 56 Fe = 56 g 26 Fe iron 55.85

7. MOLES and GRAMS 1 mole of an atom’s amu = 1 g 1 gram = 6.02 x 10 23 amu = 1 mole Si = 28.09 = 28 amu 28 amu = [ 28 Si] 28 amu x 6.02 x 10 23 = 1mole 1 mole of 28 Si = ___ g 14 Si silicon 28.09 28

8. MOLES and GRAMS 1 mole of an atom’s amu = 1 g 1 gram = 6.02 x 10 23 amu = 1 mole Si = 28.09 = 28 amu 28 amu = [ 28 Si] 28 amu x 6.02 x 10 23 = 1mole 2 moles of 28 Si = ___ g 14 Si silicon 28.09 56

9. MOLES and GRAMS 1 mole of an atom’s amu = 1 g 1 gram = 6.02 x 10 23 amu = 1 mole O = 15.999 = ___ amu 16 amu = [ 16 O] 16 amu x 6.02 x 10 23 = _ mole 4 moles of 16 O = ___ g 8 O oxygen 15.999 64 16 1

10. MOLAR MASS 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)

11. MOLECULAR MASS 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)

12. GRAMS per MOLE g/mol  how the number of GRAMS of “1” MOLE of any substance would feel (e.g.) Molecular Mass of CO 2 = 44 g/mol EXPLANATION: If you had “1” mole of a CO 2 molecule, its mass would be 44 g (the feel of “44” USA dollar bills stacked in your hand)

13. MASS in AMU you can express the MASS of an ATOM (ELEMENT) or a single molecule (COMPOUND) in AMU (atomic mass units) (e.g.) 12 C = 12 amu = 1 mole 12 C = 1 mole = 6.02 x 10 23 12 C = 12 amu = 12 g/mol = 12 g

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

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

16. 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

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

18. Avogadro’s Number: 6.02 x 10 23 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 10 23 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

19. AVOGADRO’S NUMBER and MOLES:

20. HAPPY MOLE DAY Oct 23 rd