Video Solution: Write an equation for the Brønsted–Lowry acidR...

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Organic Chemistry / Cumulative General Concepts / Problem #15961

Write an equation for the Brønsted–Lowry acid–base reaction that occurs when each of the following bases reacts with water. Show all unshared electron pairs and formal charges, and use curved arrows to track electron movement. 

Video Transcript

So, here we've got our nitrogen and it's got three bonds, right? So, is it going to want to do anything? absolutely, right? It can still attack, so we've got a lone pair that it can use to go ahead and grab a hydrogen off of this water, go ahead and do that properly, there we go, so then we know we kick electrons on to that O and we know that our water has two lone pairs and what we get is this right here with our nitrogen, right? Our nitrogen now has two hydrogens coming off of it and we've got a positive charge and no lone pair, right? And then we've got our hydroxides again with three lone pairs and a negative charge, okay? And not all of these reactions that happened that I drew up here, would actually occur because of pKa valence, right? But if they were to occur, this is how it would happen, so guys please feel free to let me know that if you have any questions, right? if not, let's move on.

Draw the Lewis structure of a molecule that has both sp2 and sp3 hybridized nitrogen atoms.

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Draw a molecule that contains at least one of each of the following:

a) an sp3 carbon

b) an sp2 carbon

c) an sp nitrogen

d) an intermediate hydrogen bond

e) an oxygen with tetrahedral electron geomtry

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Draw the electronic structure of O 2. Show all valence electrons and indicate what type of orbital they reside in. 

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For the molecule pictured:

i) Identify the circled functional groups;

ii) How many lone pairs of electrons does this molecule have?

iii) How many 1° hydrogens are present?

iv) How many sp2 carbons are present?

v) how many 3° carbons are present?

vi) How many unit of unsaturation are present?

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Draw a picture, give an example, or define to explain each of the following terms.

Hydrocarbon                                                                                  Alkyne

 

 

 

sp3 hybridized atom                                                                        2 constitutional isomers

 

 

 

aromatic                                                                                             electrophile

 

 

 

Nitric Acid                                                                                           Lewis base

 

 

 

radical                                                                                                 vinyl group

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The following structure of caffeine (a stimulant) is shown below. For each atom indicated by an arrow, determine the hybridization. Next, determine the total number of sigma (s) bonds, the total number of pi (p) bonds, and the total number of lone pairs (note: indicate number of lone pairs, not number of lone pair electrons). Don't forget about the hydrogens!

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The popular methylating agent, diazomethane has a molecular formula CH 2N2.

a) Draw the most stable Lewis structure for diazomethane.

 

 

 

b) Calculate the formal charge at each nitrogen atom for the structure you drew.

 

 

 

c) Draw the possible resonance strucutres for diazomethane and indicate which resonance form is the major contributor. 

 

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Draw a picture, give an example, or define to explain each of the following terms.

tert-butyl                                                                                                 nucleophile

 

 

 

secondary carbocation                                                                          dialkyloxonium ion

 

 

 

2° amine                                                                                               phenyloxonium ion

 

 

 

pKa                                                                                                       benzyl halide

 

 

 

H-Bond                                                                                                 nitrile

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Write two additional resonance structures that are significant for the hydrocarbon anion shown below. Put in all lone pairs, multiple bonds and formal charges. Draw the curved arrows that show the delocalization of electrons. Label your two new structures as C’ & C”. Using the information on the charge distribution and your knowledge of what makes a stable contributor, indicate which (of C, C’, & C”) is/are the major-contributing and minor- contributing resonance structures that you have assigned.

 

Using these resonance structures, identify what the approximate charge on the oxygen atom and on the central carbon would be in the resonance hybrid. A localized charge is –1). Circle your answer below.

For the oxygen atom:

(a) –0.5 (b) between –0.5 and –0.33                  (c) –0.33                    (d) less than –0.33.

For the center carbon:

(a) –0.5 (b) between –0.5 and –0.33                   (c) –0.33                    (d) less than –0.33

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Provide the valence- bond structures of all the cyclic compounds with the formula C5H6. Also provide the degree of unsaturation C5H6 formula below. Provide as many correct valence bond structures as you can.

Degrees of Saturation _______________________________

C5H6 cyclic compound

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Complete the valence - bond structure below by adding any necessary non-bonding (lone pair) electrons. Also, show any formal charges other than zero (0), then on the line describe the overall shape of the molecules (i-iv) above. Consider only carbon, nitrogen and oxygen for the overall shape. Use "linear", "planar", or "tetrehedral" to describe the shapes. In the box, show a resonance form of the compound (i) above (non- bonding electron and formal charges). 

 

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What is the  total number of pi (π) bonds  present within the structure of  Cl3CCCH?

A. 0

B. 1

C. 2

D. 3

E. 4

F. More than 5

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How many electrons in the correct Lewis structure of   Cl3CCCH are  NOT  shared in covalent bonds?

a. 18

b. 20

c. 22

d. 24

e. 26

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What is the  total number of sigma (σ) bonds  present within the structure of  N2F2?

A. 1

B. 2

C. 3

D. 4

E. 5

F. More than 5

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What is the total number of valence electrons that should be shown explicitly as bonding pairs and/or lone pairs in the correct Lewis structure for Cl2CCCH2?

A. 24        B. 25       C. 26       D. 27       E. 28

Look at the carbon atom marked with the arrow in the condensed structural formula for Cl2CCCH2 that is given in the question above. What is the geometrical arrangement of electron groups surrounding this carbon atom in Cl2CCCH2?

A. Trigonal planar

B. Tetrahedral

C. Linear

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Use line-angle (skeletal) structures (showing all lone pairs). 

A. Create the electron arrows needed to arrive at the other resonance structures for the following molecules.

B. Construct the new resonance structure produced by that shift in electrons. 

C. Classify each of them as major or minor contributors to the resonance hybrid. 

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Use line-angle (skeletal) structures (showing all lone pairs present).  A. Create the electron arrows needed to arrive at the other resonance structures for the following molecules.  B. Construct the new resonance structure produced by that shift in electrons.  C. Classify each of them as major, minor, or equal contributors to the resonance hybrid.

 

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Use line-angle (skeletal) structures (showing all lone pairs and charges present).

A) Create the electron arrows needed to arrive at the other resonance structure for the following molecule.

B) Construct the new resonance structure produced by that shift in electrons.

C) Classify each resonance structure as major. minor, or equal contributors to the resonance hybrid.

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A Lewis formula is shown on the left below. Analyze the structure and determine where you need the electron arrow(s) to generate the proper electron flow to its resonance contributors. Draw the electron arrows for each step, the resulting structures, and circle the major contributor.

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Consider a molecule with the following condensed formula:

                                                     CH3CHCHC(CH3)2COCN

 

A. Construct a dash structural formula for the compound above. Include all nonbonding electron pairs and hydrogen atoms.

 

 

 

 

B. Label the hybridization of every non-hydrogen atom.

 

 

 

 

C. Circle any polar covalent bonds.

 

 

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