L07 Chem 111A Lecture 22: Daschbach - Lecture 22

1. Which of the following reagent(s) can be used to prepare a mixture of o and p-nitro toluene from toluene

(A) HNO₂ (B) HNO₃ (C) HNO₃/Fe (D) HNO₃/H₂SO₄ (E) NaNO₂

2.

(A) H₂SO₃ (B) SO₃/ Which of the following reagent(s) can be used to convert nitrobenzene to m-nitrobenzenesulfonic acid Fe (C) H₂SO₃/Fe (D) H₂SO₄/Al₂(SO₄)₃ (E) H₂SO₄.SO₃

3. Which of the following reagent(s) can be used to prepare bromobenzene from benzene

(A) NBS (B) Br₂/FeBr₃ (C) H₂SO₄/Br₂ (D) Br₂/AlBr₃ (E) Br₂/Pd

4. Which of the following functional groups are o,p-directing ?

(A) Br, CH₂CH₃, NH₂ (B) Cl, NH₂, COOH (C) I, SO₃H, OH (D) OCH₃, Cl, COCH₃ (E) NO₂, CH₃, OH

5. Which of the following reagent(s) gives the reaction below

(A) CH₃Cl (B) Cl₂/ Fe (C) Cl₂/ AlCl₃ (D) Cl₂/ FeCl₃ (E) Cl₂/ HCl

6. Friedal-Craft acylation reagent(s)

(A) CH₃Cl/AlCl₃ (B) Cl₂/CH₃COCl (C) CH₃COCl/AlCl₃ (D) CH₃COCl/FeCl₃ (E) CH₃Cl/FeCl₃

7. Which of the following functional groups are m-directing ?

(A) NO₂, CH₃, OH (B) Br, NH₂, COOH (C) I, SO₃H, OH (D) OCH₃, Cl, COCH₃ (E) COCH_3, SO₃H, CHO

8. Which of the following compound can be used in the Diels-Alder reaction

(A) 2-methyl, 2,4-hexadiene (B) 2,5-hexadiene (C) 1-methyl,cyclohexa-1,4-diene (D) cyclohexa-1,4-diene

(E) 2-methyl, 1,5-hexadiene

9. Which statement about benzene is incorrect?

(A) The C�C p - bonding is delocalized (B) The C₆ ring is planar (C) The average C - C bond distance is the same as C-C double bonds (D) Each C atom is sp² hybridized ( E ) There are 12 s (sigma) bonds in benzene

10. Which of the following is NOT aromatic

(A) Cyclopropenyl cation (C₃H₃⁺) (B) Benzene (C₆H₆) (C) [16]-Annulene (C₁₆H₁₆)

(D) Cycloheptatrienyl cation (C₇H₇⁺) (E) [18]-Annulene (C₁₈H₁₈)

11. Conjugate addition of one equivalent of deuterium bromide (DBr) to 1,3-butadiene gives

(A) 3-bromo, 4-deutero, 1-butene (B) 3-bromo, 4-deutero, 2-butene (C) 4-bromo, 3-deutero, 1-butene (D) 1-bromo, 4-deutero, 2-butene (E) 1-bromo, 4-deutero, 1-butene

12. Which of the following is a conjugated diene

(A) cyclopentadiene (B) 2-methylcyclohexanone (C) 1-methyl,cyclohexa-1,4-diene (D) cyclohexa-1,4-diene

(E) cycloocta-1,5-diene

13. The aromatic compound is

14. Which of the following reaction involves a benzyne mechanism ?

(A) Ph-CH₃ ? Ph-COOH (B) Ph-CH₃ ? Ph-CHO (C) Ph-OH ? Ph-Cl (D) Ph-Cl ? Ph-OH

(E) none of these

15. Which of the following reagent(s) can be used to prepare a mixture of o and p-nitro toluene from

toluene

(A) HNO₂ (B) HNO₃ (C) HNO₃/Fe (D) HNO₃/H₂SO₄ (E) NaNO₂

16. Friedal-Craft alkyation reagent(s)

(A) C₂H₅Cl/AlCl₃ (B) Cl₂/CH₃COCl (C) CH₃COCl/AlCl₃ (D) CH₃COCl/FeCl₃ (E) CH₃Cl/FeCl₃

17. Which of the following functional groups are o,p-directing ?

(A) NO₂, SO₃H, CHO (B) Br, NH₂, COOH (C) I, OH, CH₃ (D) OCH₃, Cl, COCH₃ (E) COCH_3, SO₃H, Br

18. Major product in the reaction of benzene with 1-bromopropane, in the presence of AlBr₃ catalyst

(A) bromobenzene (B) n-propylbenzene (C) iso-propylbenzene (D) o-bromo-n-propylbenzene

(E) p-bromo-n-propylbenzene

19. Which of the following is the electrophile in the nitration reaction

(A) ⁺HNO₂ (B) NO₂⁺ (C) N₂+ (D) HNO₃/H₂SO₄ (E) NO₃⁺

20. Which of the following is the electrophile in the sulfonation reaction

(A) ⁺HSO₂ (B) SO₂⁺ (C) SO₃⁺ (D) SO₃/H₂SO₄ (E) HSO₃⁺

21. Which of the following is the electrophile in the Friedel-Craft acylation reaction

(A) RCO₂⁺ (B) RCO⁺ (C) CO₂⁺ (D) RX/H₂SO₄ (E) RCO₃⁺

22. The benzyne intermediate has �� p bonds

(A) 1 (B) 2 (C) 3 (D) 4 (E) 5

23. The reagent used for Allylic/benzylic bromination is:

(A) NBS (B) Br₂/ Fe (C) Br₂/ AlBr₃ (D) Br₂/ FeBr₃ (E) Br₂/ HBr

24. Which of the following is an oxidation reagent

(A) H₂SO₄ (B) KMnO₄ (C) KMnO₂ (D) NaBH₄ (E) AlCl₃

25. The formula of fuming sulfuric acid

(A) H₂SO_4.SO₃ (B) H₂SO_4.SO₂ (C) H₂SO_4.HSO₂ (D) H₂SO_4.HSO₃ (E) H₂SO_4.SO

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26. How do you prepare the following compounds, starting from benzene ?

(a). aniline (b). Iodo benzene (c). benzoic acid (d). benzylbromide (e). m-methyl benzoic acid

(f). p-nitrobenzoic acid (g) m-nitrobenzoic acid (h). p-chlorobenzenesulfonic acid (i). m-chlorobenzenesulfonic

acid (j) 3-isopropyl benzoic acid (k). 4-isopropyl toluene

27. Draw the product(s) from the following reactions showing the mechanisms

(a) 1,3-butadiene with acrylonitrile

(b) 1,3-butadiene with one eqv. HBr

(c) 1,3-cyclohexadiene with acrylonitrile

(d) 1,3-cyclohexadiene with one eqv. HBr

(e) 1,3-cyclohexadiene with two eqv. HBr

(f) cyclopentadiene with two eqv. HBr

28. How do you prepare the following compounds, starting from toluene ?

(a). benzoic acid (b). benzyl alcohol (c). m-bromobenzoic acid (d). m-methylbenzoic acid (e). m-nitro

benzoic acid (f). p-nitrobenzoic acid

29. What is/are the product(s) expected when ethylbenzene is reacted with

(a). NBS

(b). Br₂/FeBr₃

(c). KMnO₄, then H⁺

(d). fuming H₂SO₄

(e). NBS, then aq. NaOH

(f) iso-butylbromide/AlBr₃

Practice problems for exam 2 ______________

Useful Information:

h=6.626×10-34J·s.; c=3.0×108 m/sec; E=h ; E= hc ,  = h/mv; 1J = 1 kg-m2/s2 

mass of electron = 9.11 × 10-28 g, E= q + w ; 1 cal = 4.184 Joules Please Show all Work

1. Which of the following substances have standard heats of formation that are equal to zero by definition (circle your answers): H2(g), H(g), O3(g), H2O(s), H2O(l), Hg(l), Hg(s), Hg(g).

2. Limestone stalactites are formed in the reaction: Ca2+(aq) + HCO3-(aq) ïƒ CaCO3(s) + CO2(g) +

H2O(l)
If one mole of CaCO3 is produced at 298 K under one atmosphere of pressure, the reaction performs 590 calories of expansion work, pushing back the atmosphere as CO2 is formed. At the same time, 9310 calories of heat are absorbed from the environment. What is E in Kcal/mole for CaCO3.

3. What is the minimum wavelength of light in Å (1 Å = 10-8 cm) needed to provide enough energy per quantum to rupture the chemical bond in hydrogen iodide (HI). The bond dissociation energy of HI is 71.4 Kcal/mole.

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4. Sketch the shape and orientation of the following types of orbitals: s, px, dxy, dz2, dx2-y2

5. Give the values of (n) , (l) and (ml) for each orbital in the 4p subshell.

6. Write the complete electron configuration for the following: Ti 2+_____________________________________ Cr_______________________________________

N______________________________________

7. Calculate the standard enthalpy of formation (  Ho) for diamond from graphite [i.e. C (graphite) ïƒ C (diamond)] given that:

C (graphite) + O2 ïƒ CO2 (g) (  Ho = -393.5 KJ/mole) C (diamond)] + O2 ïƒ CO2 (g) (  Ho = -395.4 KJ/mole)

If 1.0g of graphite is converted to diamond, what is the energy change? Is this an endothermic or exothermic reaction?

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8. An 160 pound astronaut on his way to Mars is buzzing along at 10,000 miles per hour. (a) Express his weight in grams (one pound = 454 grams) so that you can calculate the astronaut’s wavelength (1mile/hour = 44.7 cm/sec)

(b) Suppose the astronaut detects outside his spacecraft a proton (m=1.7 x 10-24 g) from a “solar wind” moving at exactly the spacecraft velocity. What is the proton wavelength is in Å (1 Å = 10-8 cm.

9. What is the maximum number of electrons that can occupy each of the following subshells? a) 3d_________________ b) 1s____________________ c) 2p ____________________

10. Identify the element represented by the following electronic configuration.

a) [Ne] 3s2____________________

b) What is the electron configuration for the first excited state of this atom.______________

11. Determine the number of valence electrons for each element.
(a) Br___________ (b) Na _________ (c) Sn __________

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12. 175 g of Fe at 15.0oC is mixed with 225 g of H2O at 95.0oC. What is the final temperature of the mixture? The specific heats of iron= 0.448 J/g oC and water = 4.184 J/g oC). (keep in mind the following: heat gained + heat lost = 0 and q=mass x heat capacity x T)

13. (5 pts) Calculate values of ΔHrxn for the following reactions: CS2(g) + 3O2(g)  CO2(g) + 2SO2(g)

The heat of formation for the following substances is given in kJ/mol:

CS2 CO2 SO2 117.4 -393.51 -296.83

14. (6 pts) Use the electron configuration of Li and Be and determine which element has the greatest second ionization energy. Defend your answer.

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15. Mark beside each of the following processes either “exo” or “endo” according to whether you think the process will release heat or absorb heat.

a. Ca(g) ïƒ Ca(g)+2 + 2e-
b. I(g)+1e-ïƒ I(g)-1
c. Ca(g)+2 + S(g)-2 ïƒ CaS(s) d. I2(g)ïƒ 2I(g)

( ) ( ) ( ) ( )

16. (6 pts) In each of the following pairs, which of the two species is larger?
a) O-2 or Na+ b) Ti+4 or Ti+2 c) B or C d) N or N-3

17. Write down the Lewis dot structure for the following (a) N_______________ (b) Ne________________

18. THE BORN HABER CYCLE: I may have a problem on the Born Haber cycle. Please check my lecture notes to see how to set up the process and then calculate the lattice energy from the various thermodynamic quantities such as in the NaCl example below;

 H  f NaCl = -411KJ

Na(s)  Na(g)  H =108KJ
1⁄2 Cl2  Cl(g)  H = 122KJ Ionization Energy of Na  H = 496 KJ Electron affinity of Cl  H = -349KJ