HEPTANE* - (142-82-5)

Introduction

Name: heptane*; n-heptane
* IUPAC
CAS Number: 142-82-5
Chemical Formula: C7H16 or CH3(CH2)5CH3
Molar Mass: 100.20194 g
State of Matter: colorless liquid
Mass Percent: C 83.905 %; H 16.094 % 
Isomers:  2,4-dimethylpentane  •  2,2,3-trimethylbutane  •  isoheptane  •  3-ethylpentane

Classification

• organic • alkane

Uses/Function

• "As standard in testing knock of gasoline engines." 1

Physical Properties

Melting Point:*
-90.6°C 2 = 182.55 K = -131.08°F
Boiling Point:*
98°C 3 = 371.15 K = 208.4°F
98°C 4 = 371.15 K = 208.4°F

* - 1 atm pressure

Bonding

Double Bonds: 0
Triple Bonds: 0
Sigma Bonds: 22
Pi Bonds: 0
Total: 22
Carboxyl Groups: 0
Hydroxyl Groups: 0
Hybridization: all carbons are sp3
Bonding: polar covalent
Ionic Character: 10.61 %

Thermochemistry

ΔHf° (ℓ): -53.63 kcal/mol 5 = -224.39 kJ/mol
ΔHf° (g): -44.88 kcal/mol 6 = -187.78 kJ/mol
S° (ℓ): 77.92 cal/(mol•K) 7 = 326.02 J/(mol•K)
S° (g): 102.27 cal/(mol•K) 8 = 427.90 J/(mol•K)
ΔGf° (ℓ): 0.42 kcal/mol 9 = 1.76 kJ/mol
ΔGf° (g): 1.91 kcal/mol 10 = 7.99 kJ/mol
The heat of combustion is the amount of heat released when one mole of a substance undergoes combustion according to the general reaction equation:
CxHyOz + 0.25(4x+y-2z) O2 (g) → x CO2 (g) + 0.5y H2O (ℓ)

ΔHcomb° (ℓ): -1151.24 kcal = -4816.82208 kJ
ΔHcomb° (g): -1159.99 kcal = -4853.43208 kJ

For More Information

Sources

(1) - The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, 13th ed.; Budavari, S.; O'Neil, M.J.; Smith, A.; Heckelman, P. E.; Kinneary, J. F., Eds.; Merck & Co.: Whitehouse Station, NJ, 2001; entry 4679.
(2) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 3-176.
(3) - Estok, George K. Organic Chemistry: A Short Text; W.B. Saunders: Philadelphia, 1959; p 29.
(4) - Shriner, Ralph L., Fuson, Reynold C., and Curtin, David Y. The Systematic Identification of Organic Compounds, 4th ed.; John Wiley & Sons: New York, 1962; p 314.
(5) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:79.
(6) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:80.
(7) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:79.
(8) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:80.
(9) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:79.
(10) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:80.