Formula Mole Weight Critical Pressure Critical Temperature
C4H10 58.12 550.7 psia 305 F


General Description:

The hydrocarbon butane consists of four carbons and ten hydrogens. Classified as an alkane, or paraffin, hydrogen saturates the carbon atoms via covalent single bonds. Derived from the Latin term parum affinis, meaning "little affinity" for other compounds, paraffins are known for their stability and resistance to reactivity. Alkanes such as butane are non polar, thus insoluble in polar solvents such as water.

Alkanes may be separated into fractions via distillation. The lowest boiling point (3-4 carbons) is used as fuel in cigarette lighters and barbecues. Gasoline follows in the next distillation fraction (5-11 Carbons), next kerosene and jet fuel (9-16 carbons), then diesel fuel (15-25 carbons), and the highest boiling point fractionation provides lubricants and greases (26+ carbons). The greater the branching of a hydrocarbon chain, the greater the stability of the molecule and the higher the boiling point. A colorless, odorless, nontoxic, yet flammable gas, ethane is a constituent of natural gas and petroleum (75% Methane, 25% Ethane, Propane, and Butane). These "fossil fuels" were formed through the decomposition of organic matter over thousands of years and today provide a major energy source. Large amounts of the element may also be located in the atmospheres of Saturn and Jupiter.

Pressure, psia 14.7 100 500
Temperature, F 60 200 300
Compressibility, (Z) 0.9651 0.8872 0.4985
Enthalpy, Btu/lb (h) 109.9 164.0 0.175.4
Entropy, Btu/lb-R (s) 0.4997 0.5306 0.5063
Specific Heat, Btu/mol-R (Cp) 0.4002 0.5117 1.1521
k, (Cp/Cv)  1.0993 1.0715 1.0305
Sonic velocity, ft/sec 678.2 703.6 448.9
Specific volume, ft3/lb 6.30 1.08 0.14
Dynamic viscosity, lb/ft-sec 5.085E-06 6.603E-06 1.162E-05


1) Gas Flex, Flexware, Inc., Grapeville, PA, USA
2) Organic Chemistry, Paula Yurkanis Bruice, University of California, Prentice Hall, NJ, 1998
3) General Chemistry, Darrell D. Ebbing, Wayne State University, Houghton Mifflin Co., 1996

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Flexware, Inc. 2005
Jeannette, PA USA
page updated Jan. 25, 2005