THERMODYNAMIC PROPERTIES OF AIR

These tables summarize the thermodynamic properties of air

in the liquid and gaseous states. The first table refers to liquid and

gaseous air at equilibrium as a function of temperature. The tabu-

lated properties are:

p(boil): Bubble point pressure (i.e., the pressure at which boil-

ing begins as the pressure of the liquid is lowered)

p(con): Dew point pressure (pressure at which condensation

begins as the pressure of the gas is raised)

Δ

vap

H: Enthalpy of vaporization

ρ(liq): Density of the liquid phase

ρ(gas): Density of the gas phase

c

p

(liq): Specific heat capacity at constant pressure of the liquid

phase

c

p

(gas): Specific heat capacity at constant pressure of the gas

phase

Note that the normal boiling point of air, i.e., the temperature at

which p(boil) reaches 1 standard atmosphere (1.01325 bar) is 78.7

K (–194.5°C).

The second table gives the density of air as a function of tem-

perature and pressure. The horizontal lines indicate the bound-

ary between the liquid region (above) and the gas region (below).

At temperatures above 132.5 K, air is in the supercritical region

where liquid and gas cannot be distinguished.

The references give data on other thermodynamic properties

and values at additional pressures and temperatures, as well as

correlating equations.

References

1. Sytchev, V. V., Vasserman, A. A., Kozlov, A. D., Spiridonov, G. A.,

and Tsymarny, V. A., Thermodynamic Properties of Air, Hemisphere

Publishing Corp., Washington, 1987.

2. Vargaftik, N.B., Vinogradov, Y. K., and Yargin, V. S., Handbook of

Physical Properties of Liquids and Gases, Third Edition, Begell House,

New York, 1996.

Thermodynamic Properties along the Boiling and Condensation Curves

T

p(boil)

p(con)

∆

vap

H

ρ

(liq)

ρ

(gas)

c

p

(liq)

c

p

(gas)

K

bar

bar

J/g

g/mL

g/L

J/g K

J/g K

70

0.3401

0.1939 200.5

0.91444

0.980

71

0.3910

0.2292 200.8

0.90996

1.144

72

0.4478

0.2694 201.0

0.90548

1.325

73

0.5110

0.3150 200.9

0.90099

1.533

74

0.5810

0.3664 200.8

0.89650

1.761

75

0.6583

0.4242 200.5

0.89201

2.017

76

0.7435

0.4889 200.1

0.88750

2.300

77

0.8371

0.5610 199.7

0.88297

2.611

78

0.9396

0.6410 199.1

0.87843

2.953

79

1.0515

0.7295 198.5

0.87386

3.325

80

1.1736

0.8272 197.8

0.86926

3.735

81

1.3063

0.9345 197.0

0.86464

4.179

82

1.4502

1.0521 196.2

0.85999

4.665

83

1.6060

1.1806 195.3

0.85530

5.191

84

1.7742

1.3206 194.3

0.85057

5.758

85

1.9554

1.4727 193.4

0.84580

6.370

86

2.1504

1.6376 192.3

0.84099

7.029

87

2.3597

1.8160 191.3

0.83614

7.736

88

2.5839

2.0085 190.0

0.83124

8.495

89

2.8238

2.2157 188.9

0.82629

9.313

90

3.0798

2.4385 187.6

0.82128 10.19

1.881

1.261

91

3.3528

2.6773 186.3

0.81622 11.12

1.907

1.268

92

3.6434

2.9330 185.0

0.81111 12.11

1.933

1.277

93

3.9521

3.2063 183.5

0.80593 13.17

1.957

1.286

94

4.2797

3.4979 182.0

0.80069 14.31

1.981

1.295

95

4.6269

3.8084 180.5

0.79538 15.51

2.004

1.306

96

4.9942

4.1387 179.0

0.79001 16.79

2.027

1.317

97

5.3823

4.4896 177.4

0.78456 18.15

2.050

1.329

98

5.7920

4.8616 175.7

0.77903 19.59

2.073

1.342

99

6.2238

5.2558 173.9

0.77343 21.12

2.096

1.357

100

6.6785

5.6727 172.2

0.76774 22.74

2.119

1.373

6-1

T

p(boil)

p(con)

∆

vap

H

ρ

(liq)

ρ

(gas)

c

p

(liq)

c

p

(gas)

K

bar

bar

J/g

g/mL

g/L

J/g K

J/g K

101

7.1567

6.1133 170.4

0.76196 24.46

2.142

1.390

102

7.6590

6.5783 168.5

0.75609 26.29

2.166

1.409

103

8.1861

7.0685 166.5

0.75012 28.22

2.191

1.429

104

8.7387

7.5849 164.5

0.74405 30.27

2.217

1.452

105

9.3174

8.1282 162.5

0.73786 32.44

2.244

1.476

106

9.9229

8.6993 160.3

0.73156 34.74

2.273

1.503

107

10.556

9.2992 158.0

0.72513 37.17

2.303

1.532

108

11.217

9.9286 155.7

0.71856 39.75

2.336

1.564

109

11.907

10.589

153.4

0.71185 42.49

2.370

1.599

110

12.626

11.280

150.9

0.70499 45.39

2.408

1.638

111

13.375

12.004

148.3

0.69796 48.47

2.448

1.681

112

14.155

12.761

145.7

0.69075 51.74

2.492

1.729

113

14.967

13.552

143.0

0.68335 55.21

2.541

1.782

114

15.810

14.379

140.1

0.67574 58.91

2.595

1.841

115

16.687

15.242

137.1

0.66789 62.85

2.654

1.907

116

17.597

16.142

134.0

0.65980 67.04

2.721

1.981

117

18.541

17.081

130.8

0.65143 71.53

2.796

2.065

118

19.519

18.059

127.5

0.64275 76.33

2.882

2.161

119

20.534

19.078

123.9

0.63372 81.49

2.980

2.271

120

21.584

20.138

120.1

0.62431 87.03

3.094

2.398

121

22.672

21.241

116.2

0.61446 93.01

3.227

2.548

122

23.797

22.388

112.0

0.60411 99.49

3.386

2.725

123

24.961

23.579

107.6

0.59317 106.54

3.579

2.938

124

26.163

24.817

103.0

0.58154 114.26

2.817

3.199

125

27.406

26.102

97.9

0.56909 122.77

4.119

3.525

126

28.689

27.435

92.4

0.55561 132.21

4.514

3.944

127

30.014

28.817

86.5

0.54085 142.81

5.053

4.498

128

31.381

30.250

79.8

0.52439 154.89

5.831

5.264

129

32.792

31.735

72.3

0.50558 168.88

7.048

6.382

130

34.246

33.272

63.5

0.48324 185.46

9.201

8.122

131

35.745

34.864

52.9

0.45493 205.77

13.901

11.083

132

37.289

36.511

38.9

0.41434 231.32

29.272

16.445

132.5 38.079

37.356

29.8

0.38555 246.43

50.758

20.343

Density of Air in the Single-Phase Region in g/mL

Pressure in bar (1 bar = 0.1 MPa)

T/K

1

5

10

20

30

50

100

200

500

1000

70 0.9146

0.9157

0.9170

0.9195

0.9218

0.9263

0.9363

0.9528

80 0.8692

0.8703

0.8716

0.8743

0.8768

0.8816

0.8926

0.9114

90 0.003984 0.8220

0.8237

0.8271

0.8304

0.8366

0.8504

0.8735

0.9266

100 0.003556 0.01964 0.7695

0.7745

0.7792

0.7878

0.8062

0.8352

0.8969

110 0.003215 0.01725 0.03874 0.7113

0.7190

0.7324

0.7585

0.7958

0.8670 0.9479

120 0.002937 0.01548 0.03347 0.08596 0.6393

0.6651

0.7058

0.7549

0.8374 0.9201

130 0.002705 0.01408 0.02982 0.06910 0.1355

0.5687

0.6454

0.7124

0.8086 0.8950

140 0.002507 0.01294 0.02703 0.05984 0.1028

0.3183

0.5738

0.6682

0.7804 0.8720

150 0.002336 0.01199 0.02480 0.05346 0.08765 0.1878

0.4878

0.6224

0.7529 0.8506

200 0.001745 0.00881 0.01784 0.03654 0.05611 0.09789 0.2141

0.4075

0.6248 0.7582

250 0.001394 0.00700 0.01406 0.02837 0.04290 0.07249 0.1480

0.2869

0.5202 0.6788

300 0.001161 0.00581 0.01164 0.02334 0.03508 0.05859 0.1169

0.2249

0.4412 0.6114

350 0.000995 0.00498 0.00995 0.01988 0.02979 0.04950 0.09779 0.1873

0.3825 0.5555

400 0.000871 0.00435 0.00869 0.01734 0.02595 0.04300 0.08455 0.1617

0.3381 0.5091

450 0.000774 0.00386 0.00772 0.01539 0.02300 0.03808 0.07470 0.1428

0.3036 0.4700

500 0.000696 0.00348 0.00694 0.01384 0.02068 0.03420 0.06704 0.1282

0.2760 0.4367

600 0.000580 0.00290 0.00578 0.01152 0.01722 0.02847 0.05580 0.1070

0.2345 0.3830

700 0.000497 0.00248 0.00496 0.00988 0.01476 0.02441 0.04788 0.09208 0.2045 0.3416

6-2

Thermodynamic Properties of Air

Pressure in bar (1 bar = 0.1 MPa)

T/K

1

5

10

20

30

50

100

200

500

1000

800 0.000435 0.00217 0.00434 0.00865 0.01292 0.02138 0.04198 0.08096 0.1817 0.3087
900 0.000387 0.00193 0.00386 0.00769 0.01149 0.01902 0.03740 0.07231 0.1637 0.2818

1000 0.000348 0.00174 0.00347 0.00692 0.01035 0.01714 0.03373 0.06537 0.1491 0.2595
1100 0.000317 0.00158 0.00316 0.00630 0.00941 0.01560 0.03073 0.05967 0.1370 0.2406
1200 0.000290 0.00145 0.00289 0.00577 0.00863 0.01431 0.02822 0.05490 0.1267 0.2244
1300 0.000268 0.00134 0.00267 0.00533 0.00797 0.01322 0.02609 0.05084 0.1179 0.2103
1400 0.000249 0.00124 0.00248 0.00495 0.00741 0.01228 0.02426 0.04735 0.1103 0.1980
1500 0.000232 0.00116 0.00232 0.00462 0.00692 0.01147 0.02268 0.04431 0.1036 0.1870

Thermodynamic Properties of Air

6-3