Hydrocarbons exist as gases, liquids, and solids. Categorize these in terms of their carbon numbers.

Hydrocarbons can be categorized based on their carbon numbers as follows:

1. Gases: Hydrocarbons with lower carbon numbers (1-4) tend to exist as gases at room temperature and pressure. Examples include methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10).

2. Liquids: Hydrocarbons with intermediate carbon numbers (5-16) tend to exist as liquids at room temperature and pressure. Examples include pentane (C5H12), hexane (C6H14), heptane (C7H16), octane (C8H18), and decane (C10H22).

3. Solids: Hydrocarbons with higher carbon numbers (17 and above) tend to exist as solids at room temperature and pressure. Examples include nonadecane (C19H40), eicosane (C20H42), and higher molecular weight hydrocarbons.

Gases (1-4 carbon atoms):
- Methane (CH₄)
- Ethane (C₂H₆)
- Propane (C₃H₈)
- Butane (C₄H₁₀)

Liquids (5-16 carbon atoms):
- Pentane (C₅H₁₂)
- Hexane (C₆H₁₄)
- Heptane (C₇H₁₆)
- Octane (C₈H₁₈)
- Nonane (C₉H₂₀)
- Decane (C₁₀H₂₂)
- Undecane (C₁₁H₂)
- Dodecane (C₁₂H₂₆)
- Tridecane (C₁₃H₂)
- Tetradecane (C₁₄H₃₀)
- Pentadecane (C₁₅H₃₂)
- Hexadecane (C₁₆H₃₄)

Solids (17+ carbon atoms):
- Heptadecane (C₁₇H₃₆)
- Octadecane (C₁₈H₃₈)
- Nonadecane (C₁₉H₄₀)
- Eicosane (C₂₀H₄₂)
- ... (and onward, with increasing chain length)