2. “Moles”

3. MOLEis a way of translating betweengramsandamu’s • a mole is a number that helps us translate between the atomic world and our every day world • specifically “6.02 x1023” • known as: “Avogadro’s Number”

4. MOLE is a direct translation between grams and amu’s • 1 mole of an atom’s amu = 1 g • 1 gram = 6.02 x1023 amu = 1 mole • (e.g.)carbon-12 [12C] =12 amu 12 amu=6.02 x 1023 of carbon atoms 6.02 x 1023of12C = 12 grams 1 gram of12C = 1 mole of 12C

5. MOLES and GRAMS • 1 mole of an atom’s amu = 1 g • 1 gram = 6.02 x1023 amu = 1 mole Fe = 55.85 = 56 amu 56 amu =[56Fe] 56 amux 6.02 x 1023= 1mole 1 mole of 56Fe = 56 g 26 Fe iron 55.85

6. MOLES and GRAMS • 1 mole of an atom’s amu = 1 g • 1 gram = 6.02 x1023 amu = 1 mole Si = 28.09 = 28 amu 28 amu =[28Si] 28 amux 6.02 x 1023= 1mole 1 mole of 28Si = ___ g 14 Si silicon 28.09 28

7. MOLES and GRAMS • 1 mole of an atom’s amu = 1 g • 1 gram = 6.02 x1023 amu = 1 mole Si = 28.09 = 28 amu 28 amu =[28Si] 28 amux 6.02 x 1023= 1mole 2 moles of 28Si = ___ g 14 Si silicon 28.09 56

8. MOLES and GRAMS • 1 mole of an atom’s amu = 1 g • 1 gram = 6.02 x1023 amu = 1 mole O = 15.999 = ___ amu 16 amu = [16O] 16 amux 6.02 x 1023= _ mole 4 moles of 16O = ___ g 8 O oxygen 15.999 16 1 64

9. MOLAR MASS • EQUALS the MASSof“1” MOLE of a substance • it is the MASSof“1” MOLE of a single TYPE OF ATOM (an element) • if the substance consists of a molecule,themolar mass is the MASSof each individual atomin that molecule / compound • Molar Massismeasuredingrams per mole (g/mol)

10. MOLECULAR MASS • is the combined MASSof the group of atoms forming aSINGLE MOLECULE (smallest unit of a compound) • FIND by “adding” theMASSESof the atoms forming the molecule • Molecular Mass is measured in grams per mole (g/mol)

11. GRAMS per MOLE • g/mol  how the number of GRAMSof“1” MOLE of any substance would feel • (e.g.) Molecular Mass of CO2=44 g/mol • EXPLANATION: If you had “1”moleof aCO2 molecule, its masswould be 44 g (the feel of “44” USA dollar bills stacked in your hand)

12. MASS in AMU • you can express the MASSof an ATOM (ELEMENT) or a single molecule (COMPOUND) inAMU (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

13. FINDING MOLECULAR MASS: • 1st  look up the Average Atomic Massesof the molecule’s component ELEMENTS on the Periodic Table • 2nd  round each Average Atomic Massto the nearest WHOLEnumber • 3rd  use the ATOMIC MASS of each ATOM per ELEMENT in the COMPOUND • 4th  find the TOTAL SUM

14. 6 C carbon 12.01 8 O oxygen 15.999 EXAMPLE – Finding Molecular Mass 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

15. CONVERTING amu to g/mol: • seldom refer to MOLECULARMASSin amu units, but rather in g/mol • to convert amutog/mol just simply change the units FROMamuTOg/mol • “1” MOLE of any type of ATOM has a MASSingrams EQUAL TO the ATOM’s MASSmeasured in amu

16. 6 C carbon 12.01 8 O oxygen 15.999 EXAMPLE – Converting amu into g/mol: CO2 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

17. 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 pressureandtemperatureare 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

18. AVOGADRO’S NUMBER and MOLES:

19. HAPPY MOLE DAY Oct 23rd