Related Resources: thermodynamics

Individual and Universal Gas Constants

Individual and Universal Gas Constants

Universal gas constant is a physical constant that is featured in the ideal gas law and other fundamental equations in the physical sciences.

The specific heat capacities at constant pressure and constant volume processes, and the ratio of specific heat and the individual gas constant - R - for some common used "ideal gases", can be found in the table below (approximate values at 68°F (20°C) and 14.7 psia (1 atm)):

Gas or Vapor Formula Specific Heat
Capacity 		Ratio of Specific
Heats 		Individual Gas Constant R
cp
(kJ/kg K)
cv
(kJ/kg K)
cp
(Btu/lbM°F)
cv =
(Btu/lbM°F)
K =
cp / cv
cp-cv
(kJ/Kg K)
cp-cv
(ft lnf/lbm°R)
Acetone
1.47
1.32
0.35
0.32
1.11
0.15
Acetylene
C2H2
1.69
1.37
0.35
0.27
1.232
0.319
59.34
Air
1.01
0.718
0.24
0.17
1.4
0.287
53.34
Alcohol
C2H5OH
1.88
1.67
0.45
0.4
1.13
0.22
Alcohol
CH3OH
1.93
1.53
0.46
0.37
1.26
0.39
Ammonia
NH3
2.19
1.66
0.52
0.4
1.31
0.53
96.5
Argon
Ar
0.52
0.312
0.12
0.07
1.667
0.208
Benzene
C6H6
1.09
0.99
0.26
0.24
1.12
0.1
Blast furnace gas
1.03
0.73
0.25
0.17
1.41
0.3
55.05
Bromine
0.25
0.2
0.06
0.05
1.28
0.05
Butatiene
1.12
Butane
C4H10
1.67
1.53
0.395
0.356
1.094
0.143
26.5
Carbon dioxide
CO2
0.844
0.655
0.21
0.16
1.289
0.189
38.86
Carbon monoxide
CO
1.02
0.72
0.24
0.17
1.4
0.297
55.14
Carbon disulphide
0.67
0.55
0.16
0.13
1.21
0.12
Chlorine
Cl2
0.48
0.36
0.12
0.09
1.34
0.12
Chloroform
0.63
0.55
0.15
0.13
1.15
0.08
Combustion products
1
0.24
Ethane
C2H6
1.75
1.48
0.39
0.32
1.187
0.276
51.5
Ether
2.01
1.95
0.48
0.47
1.03
0.06
Ethylene
C2H4
1.53
1.23
0.4
0.33
1.24
0.296
55.08
Freon 22
1.18
Helium
He
5.19
3.12
1.25
0.75
1.667
2.08
386.3
Hexane
1.06
Hydrogen
H2
14.32
10.16
3.42
2.43
1.405
4.12
765.9
Hydrogen Chloride
HCl
0.8
0.57
0.191
0.135
1.41
0.23
42.4
Hydrogen Sulfide
H2S
0.243
0.187
1.32
45.2
Hydroxyl
OH
1.76
1.27
1.384
0.489
Methane
CH4
2.22
1.7
0.59
0.45
1.304
0.518
96.4
Methyl Chloride
CH3Cl
0.24
0.2
1.2
30.6
Natural Gas
2.34
1.85
0.56
0.44
1.27
0.5
79.1
Neon
1.03
0.618
1.667
0.412
Nitric Oxide
NO
0.995
0.718
0.23
0.17
1.386
0.277
Nitrogen
N2
1.04
0.743
0.25
0.18
1.4
0.297
54.99
Nitrogen tetroxide
4.69
4.6
1.12
1.1
1.02
0.09
Nitrous oxide
N2O
0.88
0.69
0.21
0.17
1.27
0.18
35.1
Oxygen
O2
0.919
0.659
0.22
0.16
1.395
0.26
48.24
Pentane
1.07
Propane
C3H8
1.67
1.48
0.39
0.34
1.127
0.189
35
Propene (propylene)
C3H6
1.5
1.31
0.36
0.31
1.15
0.18
36.8
Water Vapor
1.93
1.46
0.46
0.35
1.32
0.462
Steam 1 psia. 120 – 600 °F
Steam 14.7 psia. 220 – 600 °F
1.97
1.5
0.47
0.36
1.31
0.46
Steam 150 psia. 360 – 600 °F
2.26
1.76
0.54
0.42
1.28
0.5
Sulfur dioxide (Sulphur dioxide)
SO2
0.64
0.51
0.15
0.12
1.29
0.13
24.1

K = cp / cv, the specifi heat capacity ratio
cp = specifc heat in a constant pressure process
cv = specific heat in a constant volume porcess
R = Individual Gas Constant

In SI units the value of the gas constant, R, is:
R =8.314510 Pa m3 K-1 mol-1
R = 8314.510 Pa L K-1 mol-1
R = 0.08314510 bar L K-1 mol-1

Source: Various, NASA, Penn State University, Wikipedia, Standard University

Related

Link to this Webpage:

Copy Text to clipboard

Spider Optimizer

© Copyright 2000 - 2024, by Engineers Edge, LLC
www.engineersedge.com
All rights reserved
Disclaimer | Feedback
Advertising | Contact