Aromatic Hydrocarbons Flashcards

Flashcards reviewing aromatic and aliphatic compounds, their properties, and benzene structure.

What are hybrid orbitals?

Equivalent atomic orbitals that form during bonding by the rearrangement of valence electrons.

Define aromatic compound.

An organic compound that contains benzene rings as part of its structure.

Define aliphatic compound.

Hydrocarbons such as the alkanes, alkenes, and alkynes.

What structural characteristic distinguishes aromatic compounds?

Contain single benzene rings, sometimes two or more benzene rings fused together.

What structural characteristic distinguishes aliphatic compounds?

Contain single, double, and triple bonds.

How reactive are aromatic compounds, relative to aliphatic compounds?

Less reactive.

How reactive are aliphatic compounds, relative to aromatic compounds?

More reactive.

When numbering substituted benzene rings, how should they be numbered?

In a way that gives the lowest possible numbers for the substituents.

What does the circle mean inside the six-membered ring structure in benzene?

The electrons are shared by all six carbons in the ring.

Explain benzene’s structure and how it makes the molecule unusually stable.

The electron pairs in benzene are delocalized and shared by all six carbon atoms in the ring. Benzene is relatively unreactive because the electrons are harder to pull away from six carbon atoms.

How do aromatic hydrocarbons differ from aliphatic hydrocarbons?

Aromatic compounds contain benzene rings in their structures, and aliphatic hydrocarbons are straight-chain or branched-chain structures.

What properties of benzene made chemists think it was not an alkene with several double bonds?

Benzene is much less reactive than alkenes with multiple double bonds, which usually are unstable. When benzene did react, the reactions were not similar to those of alkenes.

Why was the connection between benzopyrene and cancer significant?

Benzopyrene was the first known carcinogen, and exposure to it was occupation related. After it was discovered to be a carcinogen, measures could be taken to protect the workers. The discovery also prompted scientists and medical professionals to look for other substances that could be potentially hazardous for workers.