1. Sit with your Molview Team from last week
Chem 106: Lab Week 8
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Pick up graded papers
Sit with your Molview Team from last week A E G C D B

2. Chem 106: Class/ Lab Week 8
Three activities must be accomplished today:
Turn in: Course/ Lab Manual pp ; one set with everyone’s name who contributed on the pages
Start Fermentation Today: in pairs; Course/ Lab Manual pp ; pg. 46) Record sucrose amount page 46
Complete pages 33 & 34. Have stamped before leaving. (Completed pages due Next Week)

3. If needed, laptops are available in lab or
(Course/ Lab Manual pp ) 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
Review & Turn in
Due End of Lab Today

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
Note that this question does not require expanded octets.
Goal: Connect Lewis structure of a familiar molecule to the name of the molecule geometry
Correct answer: B
Representative results from pre-general chemistry: 60-67% correct (remaining votes roughly split between C and D)
Follow-up discussion: Ask students about the lewis structure of water. Use the simulation (either the model or real molecules screen) to demonstrate the answer once a Lewis structure is agreed upon.

8. What is the electronic geometry of NH3? Linear Trigonal Planar
Tetrahedral
Trigonal Pyramidal H N H
Note that this question does not require expanded octets.
Goal: Contrast electron pair geometry with the more familiar molecule geometry of ammonia (often seen in textbook figures). Review Lewis structures.
Correct answer: C
Representative results from pre-general chemistry: 50-67% correct (next most popular answer is B)
Follow-up discussion: Ask students about the lewis structure of ammonia. Use the simulation (either the model or real molecules screen) to demonstrate the answer once a Lewis structure is agreed upon. H

9. Which of these molecules has a linear molecule geometry?
CO2 O3
Both
Neither
Note that this question does not require expanded octets.
Goal: Extend students application of VSEPR to unfamiliar molecules (carbon dioxide is frequently shown in textbooks as an examples, so many students recall their structure from memory without the need to apply geometry modelling or VSEPR). Ozone is less familiar.
Correct answer: A
Representative results from pre-general chemistry: 52% correct (next most popular answer is C)
Follow-up discussion: Ask students about the lewis structure of each. Use the simulation (either the model or real molecules screen) to demonstrate the answer once a Lewis structure is agreed upon. Follow-up slide can also be shown.
Note: While SO2 provides a more obvious contrasting case to CO2 than O3 does (and SO2 is shown in the real molecules screen of the sim), we chose to use ozone to avoid both the use of expanded octets. Additionally, there is some controversy concerning the best Lewis structure for SO2 which instructors should be aware of. Some textbooks treat it as analogous to O3, with one single and one double bond, while others give it two single bonds and an extra lone pair on S (as shown in the simulation). Both Lewis structures lead to a bent geometry.

10. Which molecule could be represented with this diagram?
BH3
CH4
NH3
NH4+
Note that this question does not require expanded octets.
Goal: Connect 3D representations to students’ Lewis structure drawings, contrasting the first row elements.
Correct answer: C
Representative results from pre-general chemistry: 70-80% correct (next most popular answer is A)
Follow-up discussion: Ask students about the number of valence electrons of B vs N.

11. What is the molecular geometry of H2S? Linear Tetrahedral
Trigonal pyramidal
Bent
Note that this question does not require the use of expanded octets.
Goal: Extend students application of VSEPR to unfamiliar molecules (water and ammonia are frequently shown in textbooks as examples, so many students recall their structure from memory without the need to apply geometry modelling or VSEPR)
Correct answer: D
Representative results from pre-general chemistry: 71% correct (next most popular answer is A)
Follow-up discussion: Ask students about the lewis structure then use the simulation (either the model or real molecules screen) to demonstrate the answer once a Lewis structure is agreed upon

12. (Course/ Lab Manual pp. 41-42; 46) Chemical Reactions: Fermentation
Start Today: in pairs

13. (Course/ Lab Manual pp. 41-42; 46) Start Today: in pairs
Record sucrose amount page 46, Have initialed before leaving lab

14. The Mole / Molar Mass
and
Molecular Formulas

15. Avogadro’s Number & The Mole
Avogadro’s number equals 1 mole ….which equals
6.022  1023 “units of anything”
How many molecules are there in one half mole of oxygen?
3.011  1023 molecules of oxygen

16. Counting by Weighing 12 red marbles @ 7g each = 84g
12 yellow 4g each=48g
55.85g Fe = x 1023 atoms Fe
32.07g S = x 1023 atoms S
Consult the Periodic Table

17. Relative Masses of 1 Mole
CaCO3 Name? g
Oxygen
32.00 g
Copper
63.55 g
Water
18.02 g
1 mole of an “ideal” gas
equals
22.4 Liters.
(A balloon diameter
of 35 cm.)
What is the volume of
1 mole of water?

18. Molar Mass
A substance’s molar mass is the mass in grams of one mole of the element or compound. (Equals the formula weight: atomic or molecular weight in grams)
Molar Mass CO2 = ?
C = grams per mole (g/mol)
O = grams per mole (g/mol)
CO 2 = grams per mole (g/mol) (16.00) = 44.01

19. Calculate the molar mass of potassium phosphate.
What do you need ?
1) Formula of potassium phosphate:
K3PO4
2) Atomic Weights
(molar mass)
K = 39.10, P = 30.97, O = 16.00
3(39.10) (16.00) =
g/mol

20. Calculate the mass in grams of 4.00 moles of sulfur.
What do you need ?
Atomic Weight sulfur (S) = 32.07
(molar mass) = g/mol
4 mol sulfur x g/mol sulfur =
128.3 g

21. Percent Composition Mass percent of an element:
For iron in (Fe2O3), iron (III) oxide = ?
Which iron ore would you buy: one high in Fe2O3 or one high in FeO, Iron (II) oxide?
55.84 / x 100 = 77.7%

22. Percent Composition
Calculate the percentage composition for all the elements in an alkaloid with the molecular formula C10H14N2.
What do you need ?
Molar mass C10H14N2
C = 12.01, H = 1.01, N = 14.01
10(12.01) + 14(1.01) + 2(14.01) = g/mol
120.1g/mol g/mol g/mol
120.1/ / /
x 100 = x 100 = x 100 =
74.02% % %

23. Compounds with the Same Formula
[ eg. C9H8O4 ]
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
Aspirin: NSAIDS COX enzymes
Plant phenolics/ flavonoids: prevention of cancer, allelopathy, antioxidants
Caffeic acid can be found in the bark of Eucalyptus globulus.[3] It can also be found in the freshwater fern Salvinia molesta[4] or in the mushroom Phellinus linteus.[5]
Caffeic acid is found at a very modest level in coffee, at 0.03 mg per 100 ml.[6] It is one of the main natural phenols in argan oil.[7]
It is found at high level in some herbs, especially thyme, sage and spearmint (at about 20 mg per 100 grams), at high levels in spices, especially Ceylon cinnamon and star anise (at about 22 mg per 100 grams), found at fairly high level in sunflower seeds (8 mg per 100 grams), and at modest levels in red wine (1.88 mg per 100 ml) and in applesauce, apricot and plum prunes (at about 1 mg per 100 grams). It is at super high level in black chokeberry (141 mg per 100 grams) and in fairly high level in lingonberry (6 mg per 100 grams).[6] It is also quite high in the South American herb yerba mate

24. Molar Comparisons of Analgesics
Complete Table and one example calculation on a separate page Attach to Molar Masses I pages to turn in
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 C9H8O
Ibuprofen C13H18O2 25
Naproxen Sodium C14H13O3Na 22.7
Acetaminophen C8H9NO2 5
28 mmol
Molar Mass Aspirin = g/mol
5.0 g / g/mol = mol = 28 mmol

25. (Course/ Lab Manual pp. 33-37)
Your Molview Team is to, complete pages 33 & 34 in lab today. Have stamped before leaving. Completed pages due Next Week: One per Team.

26. (Course/ Lab Manual pp. 38-39)
Due Next Week: Turn in one per Team or Individually

27.
DUE: 9-Oct