CHM 130 Introduction to Chemistry at Arizona College of Nursing

Correct Answer: B. 2-pentene

​​​​​​​Explanation of Correct Answer:

The structure CH₃CH=CHCH₂CH₃ is a five-carbon chain with one double bond, so the parent name is pentene. Number the chain from the end closest to the double bond. The double bond starts between carbons 2 and 3, so the correct IUPAC name is 2-pentene. 3-pentene is not used because numbering must give the lowest possible locant for the double bond. Choices with six carbons or multiple double bonds are not correct.

Correct Answer: A. Ketone

​​​​​​​Explanation of Correct Answer:

The structure shows a carbonyl group (C=O) bonded to two carbon atoms — one from the left (CH₃CH–) and one from the right (CH₂CH₃). This arrangement defines a ketone functional group. In contrast, aldehydes have the carbonyl carbon attached to at least one hydrogen, carboxylic acids include a –COOH group, and esters have a –COOR linkage. Therefore, this compound clearly contains a ketone group.

Correct Answer: B. 5-methyl-3-hexanone

​​​​​​​Explanation of Correct Answer:

First, identify the longest continuous carbon chain that includes the carbonyl carbon. The chain has six carbons, so the parent name is hexanone. The carbonyl (C=O) is in the middle of the chain, on carbon 3, so that gives us 3-hexanone. Next, look at the right side of the chain: that carbon has an extra CH₃ branch. That branch is on carbon 5 of the main chain. A methyl group on carbon 5 gives 5-methyl. Put it all together: 5-methyl-3-hexanone.

Correct Answer: B. Amide

​​​​​​​Explanation of Correct Answer:

The structure shows a carbonyl group (C=O) directly attached to a nitrogen (–C(=O)–NH–). This is the defining feature of an amide functional group. An amine would have a nitrogen attached to carbon without a carbonyl. An alcohol would contain an –OH group, which is not present here. An ester would have –C(=O)–O–R, with an oxygen bonded to the carbonyl carbon, which this compound does not have.

Correct Answer: D. Maltose

​​​​​​​Explanation of Correct Answer:

Maltose is a disaccharide composed of two glucose molecules joined by a glycosidic bond. Disaccharides form when two monosaccharides undergo a dehydration (condensation) reaction, releasing water. Maltose is commonly produced during the breakdown of starch in digestion or fermentation. In contrast, glucose, galactose, and fructose are single-unit sugars (monosaccharides) that cannot be hydrolyzed into simpler sugars.

Correct Answer: A. 1,4-butanediol

​​​​​​​Explanation of Correct Answer:

The compound HOCH₂CH₂CH₂CH₂OH has four carbon atoms (butane backbone) and two hydroxyl (–OH) groups located on the first and fourth carbons. The “diol” suffix indicates the presence of two hydroxyl groups, and the numbers specify their positions. Therefore, its correct IUPAC name is 1,4-butanediol. The other names are incorrect because they either misplace or reduce the number of hydroxyl groups present in the molecule.

Correct Answer: C. Carboxyl group, amino group, and organic R group

​​​​​​​Explanation of Correct Answer:

An amino acid contains three essential components: an amino group (–NH₂), a carboxyl group (–COOH), and an organic R group (side chain). The amino group acts as a base, the carboxyl group acts as an acid, and the R group determines the specific chemical properties of each amino acid. Together, these groups allow amino acids to link via peptide bonds to form proteins.

Correct Answer: B. (second structure) — CH₃CH₂–C(=O)–N(CH₃)₂

​​​​​​​Explanation of Correct Answer:

N,N-dimethylpropanamide is an amide derived from propanoic acid (propan-) with the –CONH₂ group converted so that both hydrogens on the nitrogen are replaced by methyl groups. That gives –C(=O)–N(CH₃)₂. The carbonyl is attached to CH₃CH₂– (the propan- part). Option B is the only structure showing an amide with two methyl groups bonded to the nitrogen and no hydrogens on that nitrogen.

Correct Answer: D. more soluble in water than heptane

​​​​​​​Explanation of Correct Answer:

1-hexanamine is more soluble in water than heptane because it contains an –NH₂ (amine) group capable of forming hydrogen bonds with water molecules. This polar interaction enhances its solubility. Heptane, on the other hand, is a nonpolar hydrocarbon lacking any functional groups that can interact with water, making it highly hydrophobic and virtually insoluble. Therefore, the polar nature of 1-hexanamine explains its greater solubility in water.