Organic Chemistry- DAT

What is the hybridization and bond angle of the atom indicated? A. sp ; 180 B. sp2 ; 109.5 C. sp2 ; 120 D. sp3 ; 109.5 E. sp3 ; 120

A. sp ; 180 This carbon is triple bonded to another carbon on the left, and single bonded to a carbon on the right. That's it, it just has 2 things around it, meaning it is sp hybridized.

Which is the most stable conformation of 2,3-dibromobutane, viewed below through Newman projection?

Answer choice B

Which of the following structures is the greatest resonance contributor for the molecule below?

B. The lone pair on the carbon gets shared with the carbon of the nitrile; this causes the nitrogen originally giving one of its lone pairs to carbon, to take it back. As this nitrogen takes back its lone pair, it now has two lone pairs! Nitrogen with 2 bonds and 2 lone pairs acquires a negative charge. This matches Choice [B]. Another reason we know Choice [B] is the correct answer is that the overall formal charge of the molecule is consistent with the one given in the question. The original molecule had a formal charge of -1. The resonance structure in Choice [B] also has a formal charge of -1. The best way to sniff out incorrect resonance structures is to pay attention to: - Charge! Resonance structures must all maintain the same overall formal charge. Atoms must maintain their proper formal charge. - Octet! Atoms cannot have more than 4 bonds. - Structure! Molecular formula and location of the atoms must be constant between resonance structures. If either change, you no longer have the same molecule and this cannot be a valid resonance structure. Choice [A] is incorrect as Nitrogen with 2 bonds and 2 lone pairs should have a -1 charge, not a +1 charge. The overall charge of the molecule is +1; this does not match the original molecule which has a charge of -1. Choice [C] is incorrect as it has an overall formal charge of -2; this does not match the original molecule which has a charge of -1. Choice [D] is incorrect as Nitrogen with 1 bond and 3 lone pairs should have a -2 charge, not a -1 charge. Since the overall charge of the molecule should be -2; this does not match the original molecule which has a charge of -1.

In a C=C bond A. hybridization occurs between the s-orbital and one p-orbital. B. hybridization occurs between the s-orbital and two p-orbitals. C. hybridization occurs between the s-orbital and three p-orbitals. D. hybridization occurs between the s- and one p-orbitals.

B. hybridization occurs between the s-orbital and two p-orbitals. In this problem we are focused on the C=C double bond. Both carbons are bound to three atoms, making them sp2. In the C=C double bond: - The pi bond is made purely by an unhybridized p-orbital. - The sigma bond is made of sp2 hybrid orbitals; since one s and two p-orbitals are involved, this is why it is called "orbital hybridization".

How many sigma (σ) and pi (π) bonds are there in the molecule below? A. 6 sigma + 0 pi B. 12 sigma + 0 pi C. 18 sigma + 0 pi D. 24 sigma + 0 pi E. 30 sigma + 0 pi

C. 18 sigma + 0 pi

What is the hybridization and bond angle of the atom indicated? A. sp ; 180 B. sp2 ; 109.5 C. sp2 ; 120 D. sp3 ; 109.5 E. sp3 ; 120

C. sp2 ; 120

How many sigma (σ) and pi (π) bonds are there in the molecule? A. 6 sigma + 3 pi B. 8 sigma + 6 pi C. 10 sigma + 3 pi D. 12 sigma + 3 pi E. 12 sigma + 6 pi

D. 12 sigma + 3 pi Every single bond is composed of 1 sigma bond, every double bond is made of 1 sigma and 1 pi bond, and every triple is formed by 1 sigma and 2 pi bonds. To determine the number of sigma (σ) bonds in the molecule, count the total number of bonds (single, double, and triple) in the molecule. Being aware of the "invisible" hydrogens bonded to each carbon is essential in determining the correct number of sigma bonds. This molecule has 6 C-C bonds and 6 C-H bonds for a total of 12 bonds, which translates to 12 sigma bonds. To determine the number of pi (π) bonds, the double and triple bonds in a molecule need to be considered. Benzene has 3 double bonds, which correlates to 3 pi bonds (Note: the 3 sigma bonds are already accounted for in the previous count).

How would one best describe the orbital required to form a σ bond? Select all that apply. I. Overlap of two s-orbitals II. Overlap of one s- and one p-orbital III. Overlap of two p-orbitals IV. Parallel overlap of two p-orbitals A. I only B. II only C. I and IV only D. I, II, and III E. I and III only

D. I, II, and III Pi bonds are always formed by the "side by side"/parallel overlap of unhybridized p-orbitals! Hence, IV is incorrect as this describes a pi bond, not a sigma bond. Sigma bonds are always formed by the direct overlap of orbitals and orbital hybridization (s and p-orbitals together). I, II, and III all describe the direct overlap of orbitals; these are all sigma bonds!

How would one best describe the orbitals required to form a Π bond? A. Parallel overlap of two s-orbitals B. Overlap of one s- and one p-orbital C. Perpendicular overlap of two p-orbitals D. Parallel overlap of two p-orbitals

D. Parallel overlap of two p-orbitals Pi bonds are always formed by unhybridized p-orbitals! Pi bonds overlap in a "side by side" or parallel conformation.

What is the hybridization and bond angle of the atom indicated? A. sp ; 180 B. sp2 ; 109.5 C. sp2; 120 D. sp3 ; 109.5 E. sp3 ; 120

D. sp3 ; 109.5

What is the hybridization and bond angle of the atom indicated? A. sp ; 180 B. sp2 ; less than 109.5 C. sp2 ; less than 120 D. sp3 ; less than 109.5 E. sp3 ; less than 120

D. sp3 ; less than 109.5 This nitrogen has 4 things around it. It has a carbon to the left, a carbon to the right, a hydrogen, and a lone pair. 4 things makes this nitrogen sp3 hybridized.

How many sigma (σ) and pi (π) bonds are there in the molecule? A. 12 sigma + 1 pi B. 14 sigma + 2 pi C. 15 sigma + 1 pi D. 16 sigma + 2 pi E. 19 sigma + 1 pi

E. 19 sigma + 1 pi