1. Mini review for final NB: This does not cover all material!

2. Units, Conversions, Powers of 10, Prefixes Errors: Sig Figs, Error propagation Statistics: Normal distribution, t-test, Q-test Equilibrium: Constant, K sp, K H, K w, separation by precipitation, acids & bases, K a, K b Titration:v e, titration curves Acid-base titrations (very) Rough outline

3. Acids & bases - buffers, HH equation Electrochemistry Nernst equation ion selective electrode Spectrophotometry Beer’s Law light, Atomic spectroscopy Mass spectrometry Isotopes, accurate mass fragmentation Chromatography – formulas Other techniques – NMR, XRay, STM (very) Rough outline

4. Molarity = Moles of solute/Liters of Solution (M) Molality = Moles of solute/Kg of Solvent (m) Mole Fraction = Moles solute/total number of moles Mass % = Mass solute/total mass x 100 Volume % = volume solute/total volume x 100 ppm = parts per million * ppb = parts per billion * Chemical concentrations * mass for solutions, volume for gasses Basic tools

5. Random error Systematic error Basic tools

6. significant figure: The number of significant digits in a quantity is the minimum number of digits needed to express the quantity in scientific notation.. Basic tools

8. The real rule: The first uncertain figure is the last significant figure. TIP: In our calculations, we retain extra insignificant digits and round off only at the end. Basic tools

9. A Gaussian curve in which μ = 0 and σ = 1. A Gaussian curve whose area is unity is called a normal error curve. In this case, the abscissa, x, is equal to z, defined as z = (x − μ)/σ. Basic tools

11. 0.11/0.2 = 0.55 For 5 measurements Q = 0.65 So…….. KEEP! Basic tools

12. Internal standard Standard addition calibration (-blanks)

13. EQUILIBRIUM NB: K = f(T) K ≠ f(concentrations)

14. K IS DIMENSIONLESS! Concentrations in mol/liter (M) pressures in atmospheres (atm) ignore solids ignore solvents EQUILIBRIUM REVERSE REACTION  reciprocal K ADD REACTIONS  Multiply Ks LE CHATELIER’S PRINCIPLE

15. SOLUBILITY PRODUCT Ksp COMMON ION EFFECT Ksp = [Ca 2+ ] 3 [PO 4 3- ] 2 = 1.0 x 10 -26 = (3x) 3 (0.10 + 2x) 2 = 1.0 x 10 -26 EQUILIBRIUM x  solubility (mols/L of Ca 3 (PO 4 ) that can disolve)

16. Gas – solution eaquilibrium K H Henry’s Law CO 2 dissolves in water: CO 2 (g) + H 2 O H 2 CO 3 (aq) K H = 3.4 x 10 -2 at a CO 2 pressure of 3 x 10 -4 atmospheres, what is the concentration of the carbonic acid in the water? H 2 CO 3 H + + HCO 3 — Ka = 4.68 x 10 -7 What is [H + ]? - What is pH? EQUILIBRIUM

17. When (BrO 3 — ) is added to a solution containing equal concentrations of Ag + and Pb 2 +, which will precipitate first and why? Ksp = 5.49 x 10 -5 for AgBrO 3 Ksp = 3.23 x 10 -5 for Pb(BrO 3 ) 2 SOLUBILITY PRODUCT Ksp SEPARATION BY PRECIPITATION Stoichiometry! BrO 3 ¯ EQUILIBRIUM

18. TITRATION STEP 1: reaction STEP 2: V e STEP 4: at equivalence STEP 5: after equivalence STOICHIOMETRY! STEP 3: before equivalence what part of analyte is left? all analyte consumed excess titrant

19. ACTIVITY

20. SOLUBILITY PRODUCT K sp GAS  SOLUTION K H WATERK W ACIDK a BASEK b PARTITION COEFF.K EQUILIBRIUM

21. WATER EQUILIBRIUM K w pH EQUILIBRIUM

22. ACID – BASE EQUILIBRIUM

23. BUFFERS NB: Equal concentrations  pH = pK a (most effective buffer)

24. Weak acid With Strong base HA  H + + A - STEP 1: reaction STEP 2: V e # mols base added = # mols acid removed

25. Weak acid With Strong base STEP 3: before equivalence BUFFER! HA  H + + A - NB: at v = v e /2 concentrations are equal  pH = pK a !

26. Weak acid With Strong base STEP 3: before equivalence BUFFER! STEP 4: at equivalence A - + H 2 O  HA + OH - K b HA  H + + A - NB: What is pH at equivalence: for titration of strong acid with strong base? and for a weak acid with a strong base > or < 7?

27. Weak acid With Strong base STEP 3: before equivalence BUFFER! STEP 4: at equivalence A - + H 2 O  HA + OH - K b STEP 5: after equivalence excess OH - HA  H + + A -

28. Electrochemistry

29. F = (6.022 x 10 23 mol -1 ) x (1.602192 x 10 -19 C) = 96,484 C mol -1 How much? – Faraday’s constant. Current = Charge/time - I = Q/t [Ampere]=[Coulomb]/[sec] Electrochemistry

31. NERNST EQUATION At 25 o C NB: multiplying the Reaction does NOT Change E

32. NERNST EQUATION

33. E = E o when activities equal 1 E = 0 at equilibrium

34. 0.50 M AgNO3(aq) 0.010 M Cd(NO3)2(aq)

35. Reference electrodes

36. Ion selective electrode Electrolysis

37. Transmittance Absorbance Beer’s Law Spectrophotometry

38. ε depends on molecule wavelength

39. Spectrophotometry λν = c [3 x 10 8 m/s] E = h ν

40. Spectrophotometry

42. The fraction of atoms in the excited state is still less than 0.02%, but that fraction has increased by 100(1.74 – 1.67)/1.67 = 4% Spectrophotometry

43. Linewidth Spectrophotometry

44. http://webbook.nist.gov/chemistry/mw-ser.html What is mass 28? N 2 CO C 2 H 4 (ethylene) H 6 B 2 (diborane) Mass spectrometry

45. 2. Mass selection: Magnetic sector Quadrupole Time-of-flight (TOF) Ion trap Fourier transform ion cyclotron resonance Ion Mobility Instrumentation NB: REQUIRE VACUUM CHAMBER 3 step program: 1.Ionize 2.Mass select 3.detect

46. Instrumentation – FT-ICR

47. STEP 1: Ion Source (1)70 eV EI (2) MALDI (3) ESI

48. 3 ways to get more out of a mass spectrum: 1.Isotopes (quantitation) 2.Exact mass (resolution + accuracy) 3.Fragmentation (MS/MS) Mass spectrometry

49. 1. Isotopes What does the mass spectrum of C look like? http://www2.sisweb.com/mstools/isotope.htm Mass spectrometry

50. 1. Isotopes What does the mass spectrum of C look like? What does the mass spectrum of C 60 look like? Elemental clues from isotope distributions http://www2.sisweb.com/mstools/isotope.htm

51. 1. Isotopes What does the mass spectrum of C look like? What does the mass spectrum of C 60 look like? Elemental clues from isotope distributions Chemical clues from isotope distributions Kinetic isotope effect

52. Isotope mass spectrometry 1. IsotopesMass spectrometry

53. 2. Mass Accuracy Where do mass differences come from? Mass resolution m/Δm http://webbook.nist.gov/chemistry/mw-ser.html Mass spectrometry

54. http://webbook.nist.gov/chemistry/mw-ser.html 2. Mass AccuracyMass spectrometry

55. 3. Fragmentation 1.electron impact 2.CID – collision induced dissociation 3.Electron capture 4.BIRD 5. Successive fragmentation: MS/MS/MS… Mass spectrometry

56. 3. Fragmentation Mass spectrometry

57. Chromatography

58. Example: V 1 = 100 mL, K = 3 (1) Extract with 500 mL (2) Extract 5 times with 100 mL And 5 times with 500 mL? Chromatography

59. Can you improve resolution by just using a longer column (to spread out the peaks further)? Not necessarily! Chromatography

60. Therefore resolution improves with square root of the column length Chromatography

61. MAJOR TYPES OF CHROMATOGRAPHY: Liquid - LC, HPLC Gas – GC (GC-MS) Capillary electrophoresis Gel electrophoresis (DNA sequencing) Chromatography

62. Novel “Micro” techniques electronic nose Nov 14, 2003 Nanotube sensor detects nerve agents Researchers in the US have made a nerve agent detector using single-walled carbon nanotubes. Eric Snow and colleagues at the Naval Research Laboratory (NRL) in Washington say that their device is simple to fabricate, extremely sensitive and intrinsically selective to specific gases. The sensor could be used in industrial and military applications (J Novak et al. 2003 Appl. Phys. Lett. 83 4026). I ~ f (receptor  Q) Chemical and nucleic acid receptors Figure 1. Gate-biased nanowire sensor