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Chem 108: Lab Week 8

Sign in Pick up papers Sit with group partners from last week’s lab. Chem 108: Lab Week 8. G. D. B. H. A. C. E.

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Chem 108: Lab Week 8

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  1. Sign in Pick up papers Sit with group partners from last week’s lab Chem 108: LabWeek 8 G D B H A C E

  2. Your A-H group has obtained 2 to 4 unknowns. Complete the experimental procedure and submit one complete group report form today with everyone’s name on the front page and including data form page & calculations for each unknown & % Yield (replacements for pg. 36) Exp. #5: What’s My Formula? Mass Evaporating Dish + Product Mass Product (Experimental) Molar Mass Product / Molar Mass Reactant x Gatekeepers x 100 = Mass Product (Exp) / Mass Reactant x 100 = Theoretical % Calculations: % Yield = actual grams of product / theoretical (calculated) grams of produc x 100 Complete Report Form DUE Today

  3. Calculations: % Yield = actual grams of product / theoretical (calculated) grams of produc x 100

  4. Exp. #5: What’s My Formula? Identificaton Unknown Sample Salt Unknown Sample Salt Unknown Sample Salt Unknown Sample Salt Experimental Calculation: Comparison to Calculation(s) for a, b, c, d FROM last week: ? ?

  5. Theoretical Mass Calculations for any Reaction Reactants Products grams (Reactant) grams (Product) Moles Molar Mass grams (P) 1 mol (R) grams (R) ? mol (P) ? grams (P) ? mol (R) grams (R) 1 mol (P) (Divide) Mass (R) (Multiply) Mass (P) by Molar "Gatekeepers” from Balanced reaction by Molar

  6. Exp. #5: What’s My Formula? % Yield Example Heating 10.00 g of an unknown determined to be sodium bicarbonate and actually obtaining 5.98 g of sodium carbonate. What is the Percent Yield? First calculate the theoretical yield. (Adaptation of your calculations last week.) Consider the calculation assumes everything was perfect & based on 100% accuracy. Reactant = 10.00 gMolar Mass = 84.00 g/mol Product = ? g (Theoretical) Molar Mass = 105.99 g/mol

  7. Theoretical Mass Calculations Reactants Products Moles grams (Reactant) grams (Product) Molar Mass ”Mole Gatekeepers” from Balanced reaction 1 mol (NaHCO3) ? mol (Na2CO3) 10.00 grams (NaHCO3) 105.99 grams (Na2CO3) ? Theoretical grams (Na2CO3) ? mol (NaHCO3) 84.00 grams (NaHCO3) 1 mol (Na2CO3) (Divide) by Molar Mass (NaHCO3) (Multiply) by Molar Mass (Na2CO3)

  8. Theoretical Mass Calculations Reactants Products ”Mole Gatekeepers” from Balanced reaction 1 mol (NaHCO3) 1 mol (Na2CO3) 10.00 grams (NaHCO3) 105.99 grams (Na2CO3) 6.31 grams (Na2CO3) 2 mol (NaHCO3) 84.00 grams (NaHCO3) 1 mol (Na2CO3) (Divide) by Molar Mass (NaHCO3) (Multiply) by Molar Mass (Na2CO3)

  9. Exp. #5: What’s My Formula? “% Yield” is used to measure the efficiency (similar to “accuracy”) of any reaction in yielding “product(s)” (on the right of an equation) versus the calculated (theoretical) amount of the product based on the amount of “reactant(s)” (from the left of the equation) using the relative number of moles of each in a balanced chemical equation. % Yield = actual grams of product / theoretical (calculated) grams of product x 100 For example, heating 10.00 g of sodium bicarbonate and actually obtaining 5.98 g of sodium carbonate. After calculating the theoretical yield: Reactant = 10.00 gMolar Mass = 84.00 g/mol Product = 6.31 g (Theoretical) Molar Mass = 105.99 g/mol % Yield = 5.98 g (actual) / 6.31g (theoretical) x 100 = 94.6%

  10. QUESTION • A synthetic reaction produced 2.45g of Ibogaine, C20H26N2O, a natural product with strong promise in treating heroin addiction, the calculated theoretical yield was 3.05g, what is the % yield? A) 19.7% B) 39.4% C) 80.3% D) 160.6%

  11. ANSWER • If a reaction produced 2.45g of Ibogaine, C20H26N2O, a natural product with strong promise in treating heroin addiction, and the theoretical yield was 3.05g, what is the % yield? • 19.7% B) 39.4% C) 80.3% D) 160.6% % yield = 2.45g / 3.05g x 100 = 80.3%

  12. Post Lab:Compounds with the Same Formula [ eg. C9H8O4 ] What’s My Formula? Aspirin 4-Hydroxyphenylpyruvic acid Dihydroxycinnamic acids: Caffeic acid (3,4-dihydroxycinnamic acid) Umbellic acid (2,4-dihydroxycinnamic acid) 2,3-Dihydroxycinnamic acid 2,5-Dihydroxycinnamic acid 3,5-Dihydroxycinnamic acid

  13. What’s My Formula?

  14. Post Lab: What’s My Formula? Comparisons of Analgesics (mmol/dose) Which analgesic has the most biologically active ingredient based on millimoles per dose (mmol/dose)? 5.0 g of each would produce the following number of doses: Formula Doses mmol/dose Aspirin C9H8O4 15.4 Ibuprofen C13H18O2 25 Naproxen Sodium C14H13O3Na 22.7 Acetaminophen C8H9NO2 5 Molar Mass Aspirin = 180.1 g/mol 5.0 g / 180.1 g/mol = 0.028 mol = 28 mmol

  15. Post Lab: Compounds with the Same Formula [ eg. C9H8O4 ] Molar Comparisons of Analgesics Calculate Moles : Doses(mmol/dose) • Which analgesic has the most biologically active ingredient based on millimoles per dose (mmol/dose)? • 5.0 g of each would produce the following number of doses: • Formula Doses mmol/dose • Aspirin C9H8O4 15.0 • Ibuprofen C13H18O2 25.0 ? • Naproxen Sodium C14H13O3Na 22.7 ? • Acetaminophen C8H9NO2 5.0 ? 1.8 mmol/dose Molar Mass Aspirin = 180.1 g/mol 5.0 g/ 180.1 g/mol = 0.028 mol/15 doses = 1.8 mmol/dose

  16. Post Lab: Submit Individually Molar Comparisons of Analgesics Calculate Moles : Doses(mmol/dose)

  17. i-clicker Quiz (Moles / Molar Masses / Nomenclature) Moles / Molar Mass and Molecular Formulas i-clicker QUIZ QUESTIONS http://chemconnections.org/general/chem108/Moles-Molar Mass Quiz.html Submit individually on-line Consult Calendar for DUE DATE

  18. Chemical Reactions • Combination (Synthesis) • Decomposition • Single Displacement • Double Displacement • Combustion: Oxidation-Reduction • Biological Reactions: Enzyme Catalysts Fermentation _________________________ Set-up Today http://www.piney.com/BabNinkasi.html)

  19. Biological ReactionsFermentation https://www.youtube.com/watch?v=vW99JEaDApY http://www.piney.com/BabNinkasi.html

  20. Chemical Reactions • Biological Reactions: Enzyme Catalysts Fermentation Set-up Today Have Dr. R. initial page before leaving lab

  21. (Course/ Lab Manual pp. 53-58) Turn in one per group with everyone’s name who contributed on the first page. If needed, laptops are available in lab or Use PCs in PS 110 http://molview.org Review & Turn in Due End of Lab Today

  22. Submit Answers to the following Questions

  23. 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.

  24. 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

  25. Chemical Reactions Select a fermentation partner; Lab Manual pp.44-45 • Combination (Synthesis) • Decomposition • Single Displacement • Double Displacement • Combustion: Oxidation-Reduction • Biological Reactions: Enzyme Catalysts Example: Fermentation pp.61-67 _________________________ http://www.piney.com/BabNinkasi.html)

  26. Moles / Molar Mass and Molecular Formulas QUIZ QUESTIONS Completed Nomenclature Tutorial http://chemconnections.org/general/chem108/Nomenclature.htm

  27. QUESTION Strychnine is often the poison of choice in murder mysteries. It has a formula of C21H22N2O2. How many moles of carbon atoms and oxygen atoms are there in one mole of strychnine? • 21 mol of carbon atoms and 1 mol of oxygen atoms • 21 mol of carbon atoms and 2 mol of oxygen atoms • 22 mol of carbon atoms and 21 mol of oxygen atoms • 2 mol of carbon atoms and 2 mol of oxygen atoms

  28. Answer Strychnine is often the poison of choice in murder mysteries. It has a formula of C21H22N2O2. How many moles of carbon atoms and oxygen atoms are there in one mole of strychnine? • 21 mol of carbon atoms and 1 mol of oxygen atoms • 21 mol of carbon atoms and 2 mol of oxygen atoms • 22 mol of carbon atoms and 21 mol of oxygen atoms • 2 mol of carbon atoms and 2 mol of oxygen atoms

  29. QUESTION How many atoms of silicon are there in 0.367 moles of silicon? A) 6.10 x 10-25 atoms Si B) 2.21 x 10 23 atoms Si C) 2.21 atoms Si D) 1.64 x 10 24 atoms Si

  30. Answer How many atoms of silicon are there in 0.367 moles of silicon? A) 6.10 x 10-25 atoms Si B) 2.21 x 10 23 atoms Si C) 2.21 atoms Si D) 1.64 x 10 24 atoms Si 0.367 mol x 6.02 x 1023 atoms/mol

  31. QUESTION Potassium phosphate and sodium phosphate is a combination medicine used to make urine more acidic to help prevent kidney stones. What is the molar mass of potassium phosphate? a) 134 g/mol b) 86.07 g/mol c) 134.07 g/mol d) 212.27 g/mol

  32. Answer Potassium phosphate and sodium phosphate is a combination medicine used to make urine more acidic to help prevent kidney stones. What is the molar mass of potassium phosphate? a) 134 g/mol b) 86.07 g/mol c) 134.07 g/mol d) 212.27 g/mol

  33. QUESTION Sulfur is derived from the Latin word sulpur. The Greek word for sulfur, θεῖον, which is the source of the international chemical prefix thio-. Sulfur is prominent in volcanic areas like Lassen National Park, which by the way stinks! What is the mass in grams of 4.00 moles of sulfur? A) 128 g B) 128.3 g C) 12.5 g D) 0.125 g

  34. Answer Sulfur is derived from the Latin word sulpur. The Greek word for sulfur, θεῖον, which is the source of the international chemical prefix thio-. Sulfur is prominent in volcanic areas like Lassen National Park, which by the way stinks! What is the mass in grams of 4.00 moles of sulfur? A) 128 g B) 128.3 g C) 12.5 g D) 0.125 g

  35. QUESTION

  36. C) 46.07 The molar mass is the sum of masses of all the atoms in the molecule. 2 12.01 + 6 1.008 + 1 16.00 = 46.07 ANSWER ´ ´ ´

  37. QUESTION

  38. C) CH Cl The molar mass has units of g/mol. (12.8 g/0.256 mol) = 50.0 g/mol. The molecule with the closest molar mass is CH ANSWER 3 Cl. 3

  39. QUESTION

  40. Answer NaOH = 6.94 mol x 40.0 g/mol

  41. B) 278 g The molar mass of sodium hydroxide, NaOH, is 22.99 g/mol + 16.00 g/mol + 1.008 g/mol = 40.00 g/mol. Convert to grams: 6.94 mol (40.00 g/mol) = 278 g. ANSWER ´

  42. QUESTION

  43. E) A ll of these The ratio of C to H in C H is 1:1. This is the same ratio found for each of the compounds, so all have the same percent composition by mass. ANSWER 8 8

  44. QUESTION Morphine, derived from opium plants, relieves pain and is addictive. It’s formula is C17H19NO3. What percent, by mass, is the carbon in this compound? 42.5% 27.9% 71.6% This cannot be solved until the mass of the sample is given.

  45. ANSWER Morphine, derived from opium plants, has the potential for use and abuse. It’s formula is C17H19NO3. What percent, by mass, is the carbon in this compound? 42.5% 27.9% 71.6% This cannot be solved until the mass of the sample is given. (17  12) / ((17  12) + (19  1) + (1  14) + 3  16)) = 0.716 0.716  100 = 71.6 %

  46. QUESTION Nearly 35 million smokers want to quit each year. Unfortunately, more than 85 percent of those who try to quit relapse, most within a week. Nicotine use is more difficult to withdraw from than heroin. What is the percent composition for nicotine, C10H14N2? A) 64.14% C, 14.04% H, 21.82% N B) 74.017 % C, 8.714 % H, 17.27 % N C) 74.02 % C, 8.71 % H, 17.27 % N D) 44.43 % C, 3.74 % H, 51.83 % N Nicotiana tobacum

  47. Answer Nearly 35 million smokers want to quit each year. Unfortunately, more than 85 percent of those who try to quit relapse, most within a week. Nicotine use is more difficult to withdraw from than heroin. What is the percent composition for nicotine, C10H14N2? A) 64.14% C, 14.04% H, 21.82% N B) 74.017 % C, 8.714 % H, 17.27 % N C) 74.02 % C, 8.71 % H, 17.27 % N D) 44.43 % C, 3.74 % H, 51.83 % N

  48. Experiment 5: What’s my formula • Report Form: One form for each Group from last week are both to be turned in; stapled together. Place your partner’s name next to yours. • Check sig figs are correct and units included • Answer post lab question. • Show calculations DUE Today

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