Question 1

People put lemon juice, a source of citric acid, on fish to quench the "fishy" smell, even on perfectly good fish fillets. What type of chemical reaction is occurring when people are quenching the fishy smell by adding lemon juice?

Accepted Answer

Adding lemon juice, which is acidic, to the fish creates an acid-base reaction where the citric acid in the lemon juice reacts with the amine compounds in the fish that cause the "fishy" smell. This reaction results in the formation of water and a salt, which does not have the same odor as the original amine compounds. Therefore, the fishy smell is diminished or eliminated.

Question 2

The IUPAC name for C₄H₈ as a straight chain is butane.

Accepted Answer

The given compound has an ambiguous structure and cannot be named as butane.

Question 3

Diamond is a hydrocarbon.

Accepted Answer

Diamond is a form of carbon, specifically an allotrope of carbon, where the carbon atoms are arranged in a crystal lattice. It does not contain hydrogen, thus it is not a hydrocarbon.

Question 4

The H-C-H angle in alkanes is 109.5°.

Accepted Answer

This is true, as the H-C-H bond angle in alkanes (such as methane, CH4) is tetrahedral and measures 109.5°.

Question 5

Which of the following formulas may be attributed to a carboxylic acid?

Accepted Answer

Carboxylic acid has the functional group -COOH which corresponds to the formula -C(O)OH. Among the given choices, only choice C has this formula.

Question 6

Chloroalkanes (R-X) have roles in which of the following applications or processes?

Accepted Answer

Chloroalkanes are versatile compounds used in various applications, including nonstick coatings and films (e.g., Teflon), refrigerants (e.g., Freons), and unfortunately, some chloroalkanes have been implicated in the destruction of the ozone layer, such as CFCs.

Question 7

Which of the following formulas may be attributed to an amine?

Accepted Answer

Amines contain a nitrogen atom bonded to alkyl or aryl groups. The formula CH₅N represents a molecule with one carbon atom and one nitrogen atom, which is consistent with the structure of an amine.

Question 8

Carbon always forms four bonds in a compound.

Accepted Answer

Carbon has four valence electrons which allows it to form four covalent bonds with other atoms. Therefore, carbon always forms four bonds in a compound.

Question 9

No other element in the periodic table is able to covalently bond with other atoms of its own kind as extensively as carbon.

Accepted Answer

This statement is true. Carbon has the unique ability to form very strong covalent bonds with other carbon atoms, leading to the formation of a vast number of different carbon-based molecules, including those that make up living organisms. This ability is due to the electron configuration of carbon, which allows it to share electrons with other atoms in multiple ways, leading to the formation of long chains, branched molecules, and rings. No other element in the periodic table can form such diverse and complex molecules through covalent bonding with itself.

Question 10

Unlike carbon, nitrogen has the potential of bonding to other atoms of itself, but cannot form long chains of nitrogen.

Accepted Answer

Nitrogen can form weak bonds with other nitrogen atoms, but it cannot form long chains like carbon due to its triple bond structure.

Question 11

Octane has a lower boiling point than decane.

Accepted Answer

This is because octane has a lower number of carbon atoms and therefore has weaker intermolecular forces between its molecules, making it easier to turn into a gas at a lower temperature. Decane, with more carbon atoms, has stronger intermolecular forces and requires a higher temperature to turn into a gas.

Question 12

Which of the following is not classified as a functional group?

Accepted Answer

The functional groups listed are the carbonyl group (A), carboxyl group (B), hydroxyl group (D), all of which are involved in chemical reactions and give molecules their specific chemical properties. The CH₃ group in an alkane, on the other hand, is a simple methyl group that does not participate in chemical reactions and is not considered a functional group.

Question 13

There are three possible isomers of molecular formula C₄H₁₀.

Accepted Answer

There are only two possible isomers of molecular formula C₄H₁₀: n-butane and isobutane (or methylpropane).

Question 14

Which of the following formulas may be attributed to a ketone?

Accepted Answer

Ketones have the general formula CnH2nO. C₄H₈O fits this formula, indicating it could be a ketone.

Question 15

When making models of n-octane, the chain appears to be linear.

Accepted Answer

The answer of When making models of n-octane, the chain...

Question 16

Which compounds typically have an unpleasant smell?

Accepted Answer

Amines typically have an unpleasant smell, often described as fishy or ammonia-like. Esters can have fruity or floral scents, alcohols can have a range of odors depending on the chain length, and ethers are generally odorless.

Question 17

Ethers were once used extensively as ________.

Accepted Answer

Ethers were commonly used as anesthetics before the development of safer and more effective alternatives.

Question 18

What is the chemical formula for methanol?

Accepted Answer

The chemical formula for methanol is CH₃OH.

Question 19

CH₃Br is an alkyl halide.

Accepted Answer

The presence of the "Br" indicates that the compound contains a halogen (specifically, bromine), and the "alkyl" prefix indicates that it is a type of organic compound that contains a carbon chain. Therefore, CH₃Br is an alkyl halide.

Question 20

Which of the following formulas may be attributed to an UNSATURATED alcohol?

Accepted Answer

An unsaturated alcohol will have a double bond (C=C) in its structure. The only formula with a double bond is option B, C4H10O.

Quiz 17: The Chemistry of Carbon