Ammonia (data page)
This page provides supplementary chemical data on ammonia.
Structure and properties
Thermodynamic properties
Phase behavior |
Triple point |
195.4 K (–77.75 °C), 6.060 kPa |
Critical point |
405.5 K (132.3 °C), 11.300 MPa |
Std enthalpy change
of fusion, ΔfusHo |
+5.653 kJ/mol |
Std entropy change
of fusion, ΔfusSo |
+28.93 J/(mol·K) |
Std enthalpy change
of vaporization, ΔvapHo |
+23.35 kJ/mol at BP of –33.4 °C |
Std entropy change
of vaporization, ΔvapSo |
+97.41 J/(mol·K) at BP of –33.4 °C |
Solid properties |
Std enthalpy change
of formation, ΔfHosolid |
? kJ/mol |
Standard molar entropy,
Sosolid |
? J/(mol K) |
Heat capacity, cp |
? J/(mol K) |
Liquid properties |
Std enthalpy change
of formation, ΔfHoliquid |
? kJ/mol |
Standard molar entropy,
Soliquid |
? J/(mol K) |
Heat capacity, cp |
80.80 J/(mol K) |
Gas properties |
Std enthalpy change
of formation, ΔfHogas |
−45.92 kJ/mol |
Standard molar entropy,
Sogas |
192.77 J/(mol K) |
Heat capacity, cp |
35.06 J/(mol K) |
Heat capacity ratio, γ
at 15°C |
1.310 |
van der Waals' constants |
a = 422.5 liter2 kPa / mole2
b = 0.03707 liter / mole |
Vapor-Liquid Equilibrium Data
P in mm Hg |
1 |
10 |
40 |
100 |
400 |
760 |
1520 |
3800 |
7600 |
15600 |
30400 |
45600 |
T in °C |
–109.1(s) |
–91.9(s) |
–79.2(s) |
–68.4 |
–45.4 |
–33.6 |
–18.7 |
4.7 |
25.7 |
50.1 |
78.9 |
98.3 |
Table data (above) obtained from CRC Handbook of Chemistry and Physics 44th ed. The (s) notation indicates equilibrium temperature of vapor over solid. Otherwise temperature is equilibrium of vapor over liquid.
Vapor pressure formula for ammonia:[1]
-
-
- log10(P) = A – B / (T – C)
where P is pressure in kPa and T is temperature in kelvins
-
-
- A = 6.67956; B = 1002.711; C = 25.215 for T = 190 K through 333 K
-
-
Vapor over Anhydrous Ammonia[2] |
Temp. |
Pressure |
ρ of liquid |
ρ of vapor |
ΔvapH |
–78 °C |
5.90 kPa |
|
|
–75 °C |
7.93 kPa |
0.73094 g/cm3 |
7.8241×10−5 g/cm3 |
|
–70 °C |
10.92 kPa |
0.72527 g/cm3 |
1.1141×10−4 g/cm3 |
|
–65 °C |
15.61 kPa |
0.71953 g/cm3 |
1.5552×10−4 g/cm3 |
|
–60 °C |
21.90 kPa |
0.71378 g/cm3 |
2.1321×10−4 g/cm3 |
|
–55 °C |
30.16 kPa |
0.70791 g/cm3 |
2.8596×10−4 g/cm3 |
|
–50 °C |
40.87 kPa |
0.70200 g/cm3 |
3.8158×10−4 g/cm3 |
1417 J/g |
–45 °C |
54.54 kPa |
0.69604 g/cm3 |
4.9940×10−4 g/cm3 |
1404 J/g |
–40 °C |
71.77 kPa |
0.68999 g/cm3 |
6.4508×10−4 g/cm3 |
1390 J/g |
–35 °C |
93.19 kPa |
0.68385 g/cm3 |
8.2318×10−4 g/cm3 |
1375 J/g |
–30 °C |
119.6 kPa |
0.67764 g/cm3 |
1.0386×10−3 g/cm3 |
1361 J/g |
–25 °C |
151.6 kPa |
0.67137 g/cm3 |
1.2969×10−3 g/cm3 |
1345 J/g |
–20 °C |
190.2 kPa |
0.66503 g/cm3 |
1.6039×10−3 g/cm3 |
1330 J/g |
–15 °C |
236.3 kPa |
0.65854 g/cm3 |
1.9659×10−3 g/cm3 |
1314 J/g |
–10 °C |
290.8 kPa |
0.65198 g/cm3 |
2.3874×10−3 g/cm3 |
1297 J/g |
–5 °C |
354.8 kPa |
0.64533 g/cm3 |
2.8827×10−3 g/cm3 |
1280 J/g |
0 °C |
429.4 kPa |
0.63857 g/cm3 |
3.4528×10−3 g/cm3 |
1263 J/g |
5 °C |
515.7 kPa |
0.63167 g/cm3 |
4.1086×10−3 g/cm3 |
1245 J/g |
10 °C |
614.9 kPa |
0.62469 g/cm3 |
4.8593×10−3 g/cm3 |
1226 J/g |
15 °C |
728.3 kPa |
0.61755 g/cm3 |
5.7153×10−3 g/cm3 |
1207 J/g |
20 °C |
857.1 kPa |
0.61028 g/cm3 |
6.6876×10−3 g/cm3 |
1187 J/g |
25 °C |
1003 kPa |
0.60285 g/cm3 |
7.7882×10−3 g/cm3 |
1167 J/g |
30 °C |
1166 kPa |
0.59524 g/cm3 |
9.0310×10−3 g/cm3 |
1146 J/g |
35 °C |
1350 kPa |
0.58816 g/cm3 |
1.0431×10−2 g/cm3 |
1124 J/g |
40 °C |
1554 kPa |
0.57948 g/cm3 |
1.2006×10−2 g/cm3 |
1101 J/g |
45 °C |
1781 kPa |
0.57130 g/cm3 |
1.3775×10−2 g/cm3 |
1083 J/g |
50 °C |
2032 kPa |
0.56287 g/cm3 |
1.5761×10−2 g/cm3 |
1052 J/g |
55 °C |
2310 kPa |
0.55420 g/cm3 |
|
|
60 °C |
2613 kPa |
0.54523 g/cm3 |
2.05×10−2 g/cm3 |
|
65 °C |
2947 kPa |
0.53596 g/cm3 |
|
|
70 °C |
3312 kPa |
0.52632 g/cm3 |
2.65×10−2 g/cm3 |
|
75 °C |
3711 kPa |
0.51626 g/cm3 |
|
|
80 °C |
4144 kPa |
0.50571 g/cm3 |
3.41×10−2 g/cm3 |
|
85 °C |
4614 kPa |
0.49463 g/cm3 |
|
|
90 °C |
5123 kPa |
0.48290 g/cm3 |
4.39×10−2 g/cm3 |
|
95 °C |
5672 kPa |
0.47041 g/cm3 |
|
|
100 °C |
6264 kPa |
0.45693 g/cm3 |
5.68×10−2 g/cm3 |
|
Temp. |
Pressure |
ρ of liquid |
ρ of vapor |
ΔvapH |
The table above gives properties of the vapor-liquid equilibrium of anhydrous ammonia at various temperatures. The second column is vapor pressure in kPa. The third column is the density of the liquid phase. The fourth column is the density of the vapor. The fifth column is the heat of vaporization needed to convert one gram of liquid to vapor. |
|
|
Vapor over Aqueous Ammonia Solution[3] |
Temp. |
%wt NH3 |
Partial Pressure
NH3 |
Partial Pressure
H2O |
0 °C |
4.72 |
1.52 kPa |
0.68 kPa |
9.15 |
3.31 kPa |
0.71 kPa |
14.73 |
6.84 kPa |
0.55 kPa |
19.62 |
11.0 kPa |
0.40 kPa |
22.90 |
14.9 kPa |
0.37 kPa |
10 °C |
4.16 |
2.20 kPa |
1.21 kPa |
8.26 |
4.96 kPa |
1.17 kPa |
12.32 |
8.56 kPa |
1.01 kPa |
15.88 |
12.68 kPa |
0.93 kPa |
20.54 |
19.89 kPa |
0.83 kPa |
21.83 |
22.64 kPa |
0.73 kPa |
19.9 °C |
4.18 |
3.65 kPa |
2.19 kPa |
6.50 |
6.11 kPa |
2.15 kPa |
6.55 |
6.13 kPa |
2.13 kPa |
7.72 |
7.49 kPa |
2.08 kPa |
10.15 |
10.75 kPa |
2.01 kPa |
10.75 |
11.51 kPa |
1.96 kPa |
16.64 |
22.14 kPa |
1.72 kPa |
19.40 |
28.74 kPa |
1.64 kPa |
23.37 |
40.32 kPa |
1.37 kPa |
30.09 °C |
3.93 |
5.49 kPa |
4.15 kPa |
7.43 |
11.51 kPa |
3.89 kPa |
9.75 |
16.00 kPa |
3.80 kPa |
12.77 |
23.33 kPa |
3.55 kPa |
17.76 |
38.69 kPa |
3.31 kPa |
17.84 |
38.81 kPa |
3.24 kPa |
21.47 |
53.94 kPa |
2.95 kPa |
40 °C |
3.79 |
8.15 kPa |
7.13 kPa |
7.36 |
17.73 kPa |
6.76 kPa |
11.06 |
29.13 kPa |
6.55 kPa |
15.55 |
47.14 kPa |
5.52 kPa |
17.33 |
57.02 kPa |
|
20.85 |
76.81 kPa |
5.04 kPa |
50 °C |
3.29 |
10.54 kPa |
11.95 kPa |
5.90 |
20.17 kPa |
11.61 kPa |
8.91 |
32.88 kPa |
11.07 kPa |
11.57 |
45.56 kPa |
10.75 kPa |
14.15 |
60.18 kPa |
10.27 kPa |
14.94 |
64.94 kPa |
10.03 kPa |
60 °C |
3.86 |
18.25 kPa |
19.21 kPa |
5.77 |
28.78 kPa |
|
7.78 |
40.05 kPa |
18.47 kPa |
9.37 |
50.09 kPa |
18.07 kPa |
9.37 |
63.43 kPa |
17.39 kPa |
Temp. |
%wt NH3 |
Partial Pressure
NH3 |
Partial Pressure
H2O |
|
Heat capacity of liquid and vapor
Spectral data
Regulatory data
Material Safety Data Sheet
The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source and follow its directions.
References
- Linstrom, P.J.; Mallard, W.G. (eds.) NIST Chemistry WebBook, NIST Standard Reference Database Number 69. National Institute of Standards and Technology, Gaithersburg MD. http://webbook.nist.gov
- ^ Lange's Handbook of Chemistry, 10th ed. page 1436
- ^ Lange's Handbook of Chemistry, 10th ed. page 1451 and 1468
- ^ Perman, Jour. Chem. Soc. 83 1168 (1903)
- ^ a b "Pure Components Properties" (Queriable database). Chemical Engineering Research Information Center. http://www.cheric.org/research/kdb/hcprop/cmpsrch.php. Retrieved 1 June 2007.
Except where noted otherwise, data relate to standard ambient temperature and pressure.
Disclaimer applies.
External links