Intro to organic chemistry

Which of the following is a hydrocarbon?

• CH₃OH
• C₂H₆
• H₂O
• CO₂

Answer explanation

A hydrocarbon contains only carbon and hydrogen atoms. C₂H₆ (ethane) is a hydrocarbon.

What is the general formula for alkanes?

• CₙH₂ₙ
• CₙH₂ₙ₊₂
• CₙH₂ₙ₋₂
• CₙH₂ₙO

Answer explanation

The general formula for alkanes is CₙH₂ₙ₊₂, representing a saturated hydrocarbon.

Which of the following molecules is an alkane?

• C₂H₄
• C₃H₆
• C₄H₁₀
• C₅H₈

Answer explanation

C₄H₁₀ (butane) is an alkane, containing only single bonds.

What type of bonding is found in hydrocarbons?

• Ionic bonding
• Metallic bonding
• Covalent bonding
• Hydrogen bonding

Answer explanation

Hydrocarbons are held together by covalent bonds, where electrons are shared.

Which of the following is an unsaturated hydrocarbon?

• C₃H₈
• C₄H₁₀
• C₂H₄
• CH₄

Answer explanation

C₂H₄ (ethene) is an unsaturated hydrocarbon because it has a double bond.

Which of the following is an isomer of C₄H₁₀?

• C₃H₈
• C₄H₈
• CH₃CH(CH₃)CH₃
• C₂H₆

Answer explanation

CH₃CH(CH₃)CH₃ is an isomer of C₄H₁₀ (butane).

What is the molecular formula of butene?

• C₄H₁₀
• C₄H₈
• C₃H₆
• C₂H₄

Answer explanation

Butene is an alkene with the molecular formula C₄H₈.

What is the definition of a hydrocarbon?

• A compound that contains only carbon and oxygen atoms
• A compound that contains only carbon and hydrogen atoms
• A compound that contains only hydrogen atoms
• A compound that contains carbon, hydrogen, and nitrogen atoms

Answer explanation

A hydrocarbon contains only carbon and hydrogen atoms.

What is the molecular formula of ethene?

• C₂H₄
• C₃H₆
• C₂H₆
• C₃H₈

Answer explanation

Ethene is an alkene with the molecular formula C₂H₄.

What is the empirical formula of hexane (C₆H₁₄)?

• C₆H₁₄
• C₃H₇
• CH₂
• C₆H₁₄O

Answer explanation

The empirical formula of hexane is CH₂, the simplest whole number ratio.