2. THE MOLE: Is the SI base unit use to measure the amount of a substance. Ex: 1 mol H 2 (g) or H 2 (g) 5 mol H 2 O(l) or 5 H 2 O (l) 3 mol NaCl(s) or 3 NaCl(s)

3. 1 mol H 2 O(l) 2 mol of H (atoms) 1 mol of O (atoms) 3 mol H 2 O(l) 6 mol of H (atoms) 3 mol of O (atoms)

4. 2 mol Al 3+ (ions) 1 mol Al 2 O 3 3 mol O 2- (ions)

5. Calculating the number of mole of particles in a compound

6. Ex. How many moles of oxide ions are in 1.5 mol Al 2 O 3. 1 st 1 mol Al 2 O 3 ---- 3 mol O 2- ions. 2 nd 1.5 mol Al 2 O 3 × 3 mol O 2- ions/mol = 4.5 mol O 2- ions. ( Answer ) ( Make sense? )

7. THE MOLE ? a box of pencils = a pack of candies = 100 tablets (1 mol) (# of “particles”) a ream of paper =500 sheets 12 pencils 50 candies a bottle of aspirins= 1 mol (atoms) = 6.02 × 10 23 atoms

8. 1 mol = 6.02 × 10 23 particles ( Avogadro’s Number)

9. atoms (Cu) particles

10. 1 mol = 6.02 × 10 23 particles ( Avogadro’s Number) atoms (Cu) molecules (CO 2 ) particles

11. 1 mol = 6.02 × 10 23 particles ( Avogadro’s Number) atoms (Cu) molecules (CO 2 ) particles formula units (NaCl)

12. 1 mol = 6.02 × 10 23 particles ( Avogadro’s Number) atoms (Cu) molecules (CO 2 ) particles formula units (NaCl) ions (Fe 2+ )

13. 1 mol = 6.02 × 10 23 particles ( Avogadro’s Number) atoms (Cu) molecules (CO 2 ) particles formula units (NaCl) ions (Fe 2+ ) electrons (e - )

14. How large the Avogadro’s Number is ? 1 mol of atoms = 6.02 × 10 23 atoms Could you count the number of atoms in 1 mol? If you are able to count one atom per second, 6.02 × 10 23 ÷ 3600 sec = 1.67 × 10 20 hours 1.67 × 10 20 hours ÷ 24 = 6.96 × 10 18 days 6.96 × 10 18 days ÷ 365 = 1.91 × 10 16 years 19, 100, 000, 000, 000, 000 years !!!!!! ( 19 pentillion one hundred quadrillions of years !!!!)

15. Mole –to– Number of Particles Conversions:

16. Calculate the number of molecules in 1.5 mol of H 2 O. 1.5 mol of H 2 O x Factor molecules H2OH2O = 9.0 x 10 23 molecules of H 2 O

17. Or just multiply the number of moles given by the Avogadro’s Number: 1.5 mol × 6.02 × 10 23 molec.H 2 O/mol = 9.0 × 10 23 molecules H 2 O.

18. Number of Particles –to– Mole Conversions:

19. Calculate the number of moles in 1.806 x 10 24 atoms of copper. 1.806 x 10 24 atoms of Cu x Factor atoms = 0.3 x 10 1 mol = 3.00 mol of Cu

20. Or just divide the number of particles given by the Avogadro’s Number: x = = 0.3 × 10 1 mol Cu = 3.00 mol Cu

21. Calculating the number of particles in a compound

22. Ex. How many atoms of each element are in 2.5 mol of N 2 O 4 ? Find the # of mol of each element & then the # of atoms present: Nitrogen (N): 2.5 mol (N 2 O 4 ) × 2 mol (N)/mol N 2 O 4 = x 6.02×10 23 atoms (N)/mol = = = 5 mol (N) 5 mol (N) 3.01 × 10 24 atoms (N) 30.1 × 10 23 =

23. Oxygen (O): 2.5 mol (N 2 O 4 ) × 4 mol (O)/mol (N 2 O 4 ) x 6.02 ×10 23 atoms (O)/mol = 10 mol (O) = = 60.2 × 10 23 = 6.02 × 10 24 atoms (O)

24. Mass and Mole.

25. Molar Mass: Is the mass in grams of one mole of any pure substance.

26. Atomic mass (Na) = 22.99 a.m.u.(atomic mass units) Molar mass (Na) = 22.99 g/mol 1 mol (Na) = 22.99 g 1 mol (Na)= 22.99 g = 6.02 × 10 23 atoms.

27. Mole – to - Mass conversions.

28. Determine the number of moles in 60.75 g of magnesium. 60.75 g (Mg) x factor = 2.5 mol (Mg) Answer Make sense?

29. You can divide the mass given by the molar mass: = 2.5 mol (Mg) Answer

30. The molar mass of a compound: M(x) M(x)

31. The molar mass of a compound Is the mass (in grams) of a mole of a compound and represents the sum of the masses of every particle that makes up the compound.

32. Example: Calculate the molar mass of Na 2 SO 4. M(Na 2 SO 4 ) = m (Na) + m (S) + m (O) = 2(23 g) + 1(32 g) + 4(16 g) = 46 g + 32 g + 64 g M(Na 2 SO 4 ) = 142 g/mol.

33. Mole – to - Mass conversions in a compound:

34. Calculate the mass of 3.25 mol of H 2 SO 4. 1 st – Calculate its molar mass: M(H 2 SO 4 ) = m (H) + m (S) + m (O) = 2(1 g) + 1(32 g) + 4(16 g) = 98 g/mol. (Molar Mass) 2 nd – Convert the 3.25 mol to g: 3.25 mol (H 2 SO 4 ) × 98 g (H 2 SO 4 )/mol = 318.5 g (H 2 SO 4 ) -- Answer

35. Volume and Mole.

36. Molar Volume: 1 mol = 22.4 dm 3 (L) any gas (For any gas at STP) STP – Standard temperature & pressure (0 o C & 1 atm)

37. Mole –to– Volume Conversion:

39. Or simple, multiply the number of mole given by the Molar Volume: 0.881 mol × 22.4 L/mol V = 19.7 L

40. Volume –to–Mole Conversion:

42. Or simple, divide the volume given by the Molar Volume: 2.00 L 22.4 L/mol = 0.089 mol

43. Mole Conversions Summary

44. 1 mol = 6.02 x 10 23 particles The molar mass 22.4 L at STP (gases)

45. Mass (g) Mol # of Particles Volume (L) (STP) Molar Mass 1 mol Molar Mass 1 mol 6.02 x 10 23 1 mol 22.4 L 1 mol