Question 1

Which of the following best explains why ethanol ($$\mathrm{CH_3CH_2OH}) is $$soluble in water?

Accepted Answer

Because ethanol can form hydrogen bonds with water molecules due to its $$-\mathrm{OH}$$ group.

Question 2

How many valence electrons does a nitrogen atom have, and how many covalent bonds does it typically form?

Accepted Answer

Nitrogen has 5 valence electrons and typically forms 3 covalent bonds.

Question 3

Which of the following statements about resonance structures is TRUE?

Accepted Answer

The resonance hybrid represents the actual structure, with electron density delocalized over the molecule.

Question 4

Given the molecular formula $$\mathrm{C_3H_8O}$$, how many constitutional isomers are possible?

Accepted Answer

3

Question 5

What is the formal charge on the oxygen atom in the hydroxide ion ($$\mathrm{OH^-}$$)?

Accepted Answer

$$-1$$

Question 6

Which of the following curved arrow movements is NOT allowed when drawing resonance structures?

Accepted Answer

Breaking a sigma bond to form a lone pair.

Question 7

Which of the following molecules has a trigonal planar geometry around its central atom?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 8

What is the bond angle in a molecule with a tetrahedral geometry?

Accepted Answer

$$109.5^\circ$$

Question 9

Which of the following best describes a constitutional isomer?

Accepted Answer

Compounds with the same molecular formula but different connectivity of atoms.

Question 10

A carbon atom in methane ($$\mathrm{CH_4$}) is $$surrounded by four groups. What is the expected geometry and bond angle?

Accepted Answer

Tetrahedral, $$109.5^\circ$$

Question 11

Which of the following is a correct statement about the major contributor to a resonance hybrid?

Accepted Answer

It has more bonds and fewer charges than minor contributors.

Question 12

Which of the following best explains why the bond angle in water ($$\mathrm{H_2O}) is $$less than the ideal tetrahedral angle?

Accepted Answer

Because lone pairs on oxygen repel the bonding pairs, compressing the bond angle.

Question 13

Which of the following is the correct electron configuration for a neutral carbon atom?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^2$$

Question 14

Which of the following is a valid Lewis structure for ethylene ($$\mathrm{C_2H_4}$$)?

Accepted Answer

Each carbon forms two single bonds to hydrogen and a double bond to the other carbon.

Question 15

Which of the following statements about atomic orbitals is correct?

Accepted Answer

An s-orbital is spherical and a p-orbital is dumbbell-shaped.

Question 16

Which of the following is a correct application of the octet rule in resonance structures for second-row elements?

Accepted Answer

Second-row elements can have less than eight electrons, but never more.

Question 17

In the context of organic chemistry, which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of a pair of electrons between two atoms.

Question 18

Which of the following is a real-world example of a molecule with resonance stabilization?

Accepted Answer

Benzene ($$\mathrm{C_6H_6})$$

Question 19

Which of the following best describes the difference between resonance structures and constitutional isomers?

Accepted Answer

Resonance structures differ in the arrangement of electrons only, while constitutional isomers differ in the connectivity of atoms.

Organic Chemistry Lecture I: Structure and Bonding

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