Question 1

Which of the following best explains why carbon is able to form such a wide diversity of organic molecules?

Accepted Answer

Carbon can form up to four covalent bonds, allowing for branching and ring structures.

Question 2

What is the bond angle in a tetrahedral molecule, such as methane ($$CH_4$$)?

Accepted Answer

$$109.5^\circ$$

Question 3

Which of the following statements about isomers is correct?

Accepted Answer

Structural isomers have the same molecular formula but different covalent arrangements of their atoms.

Question 4

A molecule with the formula $$C_4H_{10}$$ can exist as either butane or isobutane. What type of isomerism does this represent?

Accepted Answer

Structural isomerism

Question 5

Which of the following best describes a functional group?

Accepted Answer

A specific group of atoms within a molecule that is responsible for certain chemical reactions.

Question 6

Which functional group is found in all amino acids and acts as a weak base?

Accepted Answer

Amino group ($$-NH_2$)

Question 7

Which of the following functional groups is nonpolar and often found in lipids?

Accepted Answer

Methyl group ($$-CH_3$)

Question 8

A molecule contains a carbon double-bonded to an oxygen atom ($$C=O) at $$the end of its carbon skeleton. Which functional group does this describe?

Accepted Answer

Aldehyde (a type of carbonyl group)

Question 9

Which of the following is true about cis-trans isomers?

Accepted Answer

They have the same covalent bonds but differ in spatial arrangement due to inflexible double bonds.

Question 10

Enantiomers are important in pharmaceuticals because:

Accepted Answer

They can have drastically different biological effects despite having the same molecular formula.

Question 11

Which functional group is responsible for the acidic properties of organic acids such as amino acids?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 12

A molecule with the formula $$C_2H_4$$ has a double bond between its carbon atoms. What is the bond angle around each carbon atom?

Accepted Answer

$$120^\circ$$

Question 13

Which of the following best describes the difference between a ketone and an aldehyde?

Accepted Answer

A ketone has a carbonyl group within the carbon skeleton, while an aldehyde has it at the end.

Question 14

Which functional group is essential for the formation of disulfide bridges in proteins?

Accepted Answer

Sulfhydryl group ($$-SH)$$

Question 15

A researcher is studying a molecule that is polar, found in alcohols, and can form hydrogen bonds. Which functional group is most likely present?

Accepted Answer

Hydroxyl group ($$-OH)$$

Question 16

Which of the following best explains why rotation is restricted around a carbon-carbon double bond?

Accepted Answer

The presence of a pi bond in addition to a sigma bond prevents free rotation.

Question 17

Which functional group is commonly found in nucleic acids and is responsible for their acidic properties?

Accepted Answer

Phosphate group ($$-PO_4$^{2-})$$

Question 18

A molecule has the same molecular formula as another but differs in the spatial arrangement of its atoms around a double bond. What type of isomerism is this?

Accepted Answer

Cis-trans (geometric) isomerism

Question 19

Which of the following statements about enantiomers is correct?

Accepted Answer

They are non-superimposable mirror images of each other.

Question 20

A patient is given two drugs with the same molecular formula but different three-dimensional arrangements. One is effective, the other is not. What is the most likely explanation?

Accepted Answer

The drugs are enantiomers, and only one form interacts correctly with the biological target.

Ch. 4 study guide

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