Chem 108: Lab Week 9

1. Chem 108: LabWeek 9 Sign in Confer with partners from last week & week before. DO: Alcohol Distillation To do with Fermentation / Chemical Reactions partner. Turn in Chemical Reactions Report form;(Confer with Molview Group if necessary) Turn in Molview Modeling form with Molview group.

2. DUE Today Chemical Reactions One report with everyone’s name • Laboratory Manual: Report Form pp.46-52 DUE Today _________________________

3. DUE Today: One report with everyone’s name Molecular Modeling http://chemconnections.org/general/chem108/Chemistry%20108%20Molecular%20Modeling%20Form%20Fall%202017.pdf http://molview.org

4. Prepare Answers to the following Questions for Next Week

5. Which of the following bonds is the most polar? A) B) C) D)

6. In which of the compounds below is the d+ for H the greatest (highest difference in e.n.)? A) CH4 B) NH3 C) SiH4 D) H2O

7. What molecular shape is water? • Tetrahedral • Bent • Trigonal planar • Linear

8. What is the electronic geometry of NH3? • Linear • Trigonal Planar • Tetrahedral • Trigonal Pyramidal H N H H

9. Which of these molecules has a linear molecule geometry? • CO2 • O3 • Both • Neither

10. Which molecule could be represented with this diagram? • BH3 • CH4 • NH3 • NH4+

11. What is the molecular geometry of H2S? • Linear • Tetrahedral • Trigonal pyramidal • Bent

12. Chemical Reactions To DO Today Biological Reactions: Enzyme Catalysts Fermentation / Distillationpp.63-47 _________________________ http://www.piney.com/BabNinkasi.html)

13. Energy: Heat: Enthalpy (ΔH)

16. Distillation http://chemconnections.org/general/movies/html-swf/oil-refining.swf Oil Refining: http://science.howstuffworks.com/oil-refining4.htm

17. Theoretical & Percent Yield http://chemconnections.org/general/movies/html-swf/oil-refining.swf

18. Theoretical Yield% Ethanol from Density

19. Calculations

20. Example 24.55 g 52.2 mL 0.990 g/mL

21. Example 24.55 g 4.5 % 52.2 mL 0.990 g/mL

22. Theoretical Yield Calculation 24.55 g ? g (theoretical) 4 Molar mass = 342.3 g/mol Molar mass = 46.07 g/mol ? mol C2H5OH= 4 x mol sucrose = 0.2869 mol ? mol sucrose = 24.55 g / 342.3 g/mol = 0.07172 mol ? g (theoretical) = mol C2H5OH x 46.07 g/mol = 13.22 g __________________ ? g (actual) = [4.5 %,that is: 4.5/100] x 52.2 mL x 0.990 g/mL = 2.33g % Yield = g (actual) / g (theoretical) x 100 = 17.6 %

23. Theoretical & Percent Yield

25. Molecular Modeling Computational Chemistry Covalent Bonds: Lewis Structures, Molecular Shapes Dr. Ron Rusay

26. Molecular Modeling Computational Chemistry Shapes Lewis Structures Polarity, Solubility, Stereochemistry Smell, Teratogenicity Dr. Ron Rusay

27. Shapes of Molecules https://www.youtube.com/watch?v=Jq_Ca-HKh1g View: What is the shape of a molecule?George Zaidan and Charles Morton http://chemconnections.org/general/chem108/Molecular%252520Shapes-Guide.html

28. Molecular Shapes Molecular Models for C, H, N, O • Fundamental repeating shapes found in every biological molecule C =black H = gray N = blue O = red pink = generic atom

29. Professor Gilbert Newton Lewis (circa 1940) G.N. Lewis Photo Bancroft Library, University of California/LBNL Image Library Footnote: G.N. Lewis, despite his insight and contributions to chemistry, was never awarded the Nobel prize. Notes from Lewis’s notebook and his “Lewis” structure.

30. Valence Electrons – Lewis Dot Drawings A Groups-Periods 2 & 3 .H

31. O two bonds three bonds N four bonds C Covalent Bond Numbers (Neutral Atoms!) one bond H F Cl Br I .H

32. (Handout) Due End of Lab Next Week

33. Lewis Structures Molecular Shapes • For simple Lewis structures: • Draw the individual atoms using dots to represent the valence electrons. • Put the atoms together so they share PAIRSof electrons to make complete octets. • NH3, for example: Eg. Ammonia:

34. http://molview.org Molecular Shapes Lewis Structures MolView: Visual On-line Molecular Modeling Bonding, Lewis Structures, Molecular Modeling: Computational Experiments, Instructions, & Manual pp. 53-58

35. http://molview.org (Course/ Lab Manual pp. 53-58) Organize Today with your Moleview Group Due End of Lab Next Week

36. Orbital (Electronic) Geometry Molecular Geometry Bond Angle # of lone pairs Important in Organic Compounds Linear Linear Trigonal Planar Trigonal Planar Trigonal Planar Bent Tetrahedral Tetrahedral Tetrahedral Trigonal Pyramidal Tetrahedral Bent Trigonal Bipyramidal Trigonal Bipyramidal Trigonal Bipyramidal Seesaw Trigonal Bipyramidal T-shape Trigonal Bipyramidal Linear Octahedral Octahedral Octahedral Square Pyramidal Octahedral Square Planar 0 0 1 0 1 2 0 1 2 3 0 1 2 See again in Chem 120 and possiblyin Chem 109

37. http://chemconnections.org/general/movies/Lewis%20structures.htmlhttp://chemconnections.org/general/movies/Lewis%20structures.html

38. Covalent Compounds • Share valence electrons. • 1 pair = 1 bond; maximum # of atom-atom bonds = 3. • Octet rule (“duet” for hydrogen) • Lewis structure examples: Notice the charges: In one case they balance, can you name the compound? In the other they do not. It has a “Formal” charge. Can you name the polyatomic ion?

39. http://molview.org Molecular Shapes Lewis Structures MolView: Polyatomic Ions Bonding, Lewis Structures, Molecular Modeling:

40. Resonance • Occurs when more than one valid Lewis structure can be written for a particular molecule. [Adjacent free electrons, double or triple bonds.] • These are resonance structures. The actual structure is an average of all of the resonance structures.

41. Infrared- Bond Absorbances

42. Infrared- Bond Absorbances http://molview.org

43. Infrared- Bond Absorbances https://www.co2.earth/

44. Computational Chemistry Polarity: Molview (http://molview.org) Jmol Color coded electron density distribution: red-highest, blue lowest, green balanced The more distinct the red –blue colors means the more polar the molecule.

45. The Lotus flower • Water & dirt repellancy: solubility? Polarity & Physical PropertiesOzone and Water 0.1278 nm • Resultant Molecular Dipoles > 0 • Solubility: Polar molecules that dissolve or are dissolved in like molecules

46. Amino Acids Legos of Chemical Biology Amino acids contain carbon, hydrogen, oxygen, and nitrogen, which resemble the following shapes & structural components • 20 different amino acids are encoded by the genetic code, which is archived in DNA. • Hundreds of amino acids link together with amide (peptide) bonds to form proteins, which are the machinery for the chemistry of life. • There are less than 20,000 total proteins produced from humans’ entire genome, each coded by a specific gene in DNA’s ~3 billion genetic bases.

47. Amino Acids Proteins Indispensible Biopolymers Acetylcholinesterase (ACE) ACE, an enzyme, which catalyzes a key reaction in a repetitive biochemical cycle that is crucial to neurological and physiological functions in humans…. and insects among others. 4,496 atoms; 4,404 bonds 574 amino acid residues

48. Biological Reactionseg. Fermentation https://www.youtube.com/watch?v=vW99JEaDApY http://www.piney.com/BabNinkasi.html

49. https://www.youtube.com/watch?v=OKRJ73Ro5jw https://www.youtube.com/watch?v=rL14uLbSLLc