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Melting Boiling Temperature Hydrocarbons Alkane Alkene Benzene Aromatic Alcohol Acid Naphthalene

Reference data and engineering information about melting boiling temperature hydrocarbons alkane alkene benzene aromatic alcohol acid naphthalene for thermodynamics applications.

meltingboilingtemperaturehydrocarbons

Overview

Engineering reference data for Melting Boiling Temperature Hydrocarbons Alkane Alkene Benzene Aromatic Alcohol Acid Naphthalene in thermodynamics.

Key Formulas

First Law

ΔU=Q−W\Delta U = Q - W

Energy is conserved — heat added minus work done.

Ideal Gas Law

PV=nRTPV = nRT

Relates pressure, volume, and temperature of an ideal gas.

Heat Transfer

Q=mcΔTQ = mc\Delta T

Sensible heat transfer.

Carnot Efficiency

η=1−TC/TH\eta = 1 - T_C/T_H

Maximum efficiency between two temperatures.

Variables

Symbol Description Unit
UU Internal energy J
QQ Heat J
WW Work J
PP Pressure Pa
VV Volume m³
TT Temperature K

Hydrocarbon Classification and General Formulas

General molecular formulas for the main hydrocarbon families:

Hydrocarbon Type General Formula Also Called
Alkane CnH2n+2\text{C}_n\text{H}_{2n+2} Paraffin
Alkene CnH2n\text{C}_n\text{H}_{2n} Olefine
Alkyne CnH2n−2\text{C}_n\text{H}_{2n-2} Acetylene
Cycloalkane CnH2n\text{C}_n\text{H}_{2n} Naphthene
Cycloalkene CnH2n−2\text{C}_n\text{H}_{2n-2} Cycloolefin
Benzene (aromatic) C6H6\text{C}_6\text{H}_6 —
Naphthalene (polycyclic aromatic) C10H8\text{C}_{10}\text{H}_8 —

Where nn = number of carbon atoms.

Boiling Point Trend

For hydrocarbons with the same carbon number, boiling points increase in the following order:

  1. Multi-substituted alkanes (e.g., 2,2-dimethylalkane) — lowest
  2. Single-substituted alkanes (e.g., 2-methylalkane)
  3. Single-substituted alkenes (e.g., 2-methylalkene)
  4. Normal alkenes (1-alkene)
  5. Normal alkanes (n-alkane)
  6. Alkylcyclohexanes
  7. Alkylbenzenes
  8. Cycloalkenes / Cycloalkanes
  9. 2-Alkanols / 4-Alkanols / 1-Alkylnaphthalenes
  10. 1-Alkanols
  11. Normal alkanoic acids — highest

Key principle: Branching lowers boiling point (reduced surface area for intermolecular forces), while hydrogen bonding functional groups (alcohols, carboxylic acids) and ring structures significantly raise it.

Boiling Points of Hydrocarbons, Alcohols and Acids (°C)

References