Ammonia (data page)

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This page provides supplementary chemical data on ammonia.

==Structure and properties== <!-- KEEP this header, it is linked to from the infobox on the main article page -->

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! | Molecular structure

|-

| Point group

| C_3v

|-

| Bond length

| 101.2 pm (N–H)

|-

| Bond angle

| 106.7° (H–N&ndash;H)

|-

| Standard molar entropy,<br/>S^<s>o</s>_liquid

| ? J/(mol K)

|-

| Heat capacity, c_p

| 80.80 J/(mol K)

|-

! | Gas properties

|-

| Std enthalpy change<br/>of formation, Δ_fH^<s>o</s>_gas

| &minus;45.556 ± 0.029 kJ/mol

|-

| Std Gibbs free energy change<br/>of formation, Δ_fG^<s>o</s>_gas

| &minus;16.6 kJ/mol<!--From -3.976 kcal/mol from CRC 48th ed.-->

|-

| Standard molar entropy,<br/>S^<s>o</s>_gas

| 192.77 J/(mol K)

|-

| Heat capacity, c_p

| 35.06 J/(mol K)

|-

| Heat capacity ratio, γ<br>at 15&nbsp;°C

| 1.310

|-

| van der Waals' constants

| a = 422.5 L² kPa/mol²<br> b = 0.03707 L/mol

|-

|}

Vapor–liquid equilibrium data

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| | 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.

thumb|666px|left|log₁₀ of anhydrous ammonia vapor pressure. Uses formula shown below.

Vapor-pressure formula for ammonia:

: log₁₀P = 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.

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{| border="1" cellspacing="0" cellpadding="6" style="margin: 0 0 0 0.5em; background: white; border-collapse: collapse; border-color: #C0C090;"

! colspan="5" | Vapor over anhydrous ammonia

|-

| bgcolor="E0E0E0" align="center" | Temp.

| bgcolor="E0E0E0" align="center" | Pressure

| bgcolor="E0E0E0" align="center" | ρ of liquid

| bgcolor="E0E0E0" align="center" | ρ of vapor

| bgcolor="E0E0E0" align="center" | Δ_vapH

|-

| −78&nbsp;°C || 5.90 kPa

| ||

|-

| −75&nbsp;°C || 7.93 kPa

| 0.73094 g/cm³

| 7.8241&times;10⁻⁵ g/cm³

|

|-

| −70&nbsp;°C || 10.92 kPa

| 0.72527 g/cm³

| 1.1141&times;10⁻⁴ g/cm³

|

|-

| −65&nbsp;°C || 15.61 kPa

| 0.71953 g/cm³

| 1.5552&times;10⁻⁴ g/cm³

|

|-

| −60&nbsp;°C || 21.90 kPa

| 0.71378 g/cm³

| 2.1321&times;10⁻⁴ g/cm³

|

|-

| −55&nbsp;°C || 30.16 kPa

| 0.70791 g/cm³

| 2.8596&times;10⁻⁴ g/cm³

|

|-

| −50&nbsp;°C || 40.87 kPa

| 0.70200 g/cm³

| 3.8158&times;10⁻⁴ g/cm³

| 1417 J/g

|-

| −45&nbsp;°C || 54.54 kPa

| 0.69604 g/cm³

| 4.9940&times;10⁻⁴ g/cm³

| 1404 J/g

|-

| −40&nbsp;°C || 71.77 kPa

| 0.68999 g/cm³

| 6.4508&times;10⁻⁴ g/cm³

| 1390 J/g

|-

| −35&nbsp;°C || 93.19 kPa

| 0.68385 g/cm³

| 8.2318&times;10⁻⁴ g/cm³

| 1375 J/g

|-

| −30&nbsp;°C || 119.6 kPa

| 0.67764 g/cm³

| 1.0386&times;10⁻³ g/cm³

| 1361 J/g

|-

| −25&nbsp;°C || 151.6 kPa

| 0.67137 g/cm³

| 1.2969&times;10⁻³ g/cm³

| 1345 J/g

|-

| −20&nbsp;°C || 190.2 kPa

| 0.66503 g/cm³

| 1.6039&times;10⁻³ g/cm³

| 1330 J/g

|-

| −15&nbsp;°C || 236.3 kPa

| 0.65854 g/cm³

| 1.9659&times;10⁻³ g/cm³

| 1314 J/g

|-

| −10&nbsp;°C || 290.8 kPa

| 0.65198 g/cm³

| 2.3874&times;10⁻³ g/cm³

| 1297 J/g

|-

| −5&nbsp;°C || 354.8 kPa

| 0.64533 g/cm³

| 2.8827&times;10⁻³ g/cm³

| 1280 J/g

|-

| &nbsp;0&nbsp;°C || 429.4 kPa

| 0.63857 g/cm³

| 3.4528&times;10⁻³ g/cm³

| 1263 J/g

|-

| &nbsp;5&nbsp;°C || 515.7 kPa

| 0.63167 g/cm³

| 4.1086&times;10⁻³ g/cm³

| 1245 J/g

|-

| &nbsp;10&nbsp;°C || 614.9 kPa

| 0.62469 g/cm³

| 4.8593&times;10⁻³ g/cm³

| 1226 J/g

|-

| &nbsp;15&nbsp;°C || 728.3 kPa

| 0.61755 g/cm³

| 5.7153&times;10⁻³ g/cm³

| 1207 J/g

|-

| &nbsp;20&nbsp;°C || 857.1 kPa

| 0.61028 g/cm³

| 6.6876&times;10⁻³ g/cm³

| 1187 J/g

|-

| &nbsp;25&nbsp;°C || 1003 kPa

| 0.60285 g/cm³

| 7.7882&times;10⁻³ g/cm³

| 1167 J/g

|-

| &nbsp;30&nbsp;°C || 1166 kPa

| 0.59524 g/cm³

| 9.0310&times;10⁻³ g/cm³

| 1146 J/g

|-

| &nbsp;35&nbsp;°C || 1350 kPa

| 0.58816 g/cm³

| 1.0431&times;10⁻² g/cm³

| 1124 J/g

|-

| &nbsp;40&nbsp;°C || 1554 kPa

| 0.57948 g/cm³

| 1.2006&times;10⁻² g/cm³

| 1101 J/g

|-

| &nbsp;45&nbsp;°C || 1781 kPa

| 0.57130 g/cm³

| 1.3775&times;10⁻² g/cm³

| 1083 J/g

|-

| &nbsp;50&nbsp;°C || 2032 kPa

| 0.56287 g/cm³

| 1.5761&times;10⁻² g/cm³

| 1052 J/g

|-

| &nbsp;55&nbsp;°C || 2310 kPa

| 0.55420 g/cm³ ||

||

|-

| &nbsp;60&nbsp;°C || 2613 kPa

| 0.54523 g/cm³

| 2.05&times;10⁻² g/cm³

|

|-

| &nbsp;65&nbsp;°C || 2947 kPa

| 0.53596 g/cm³ ||

||

|-

| &nbsp;70&nbsp;°C || 3312 kPa

| 0.52632 g/cm³

| 2.65&times;10⁻² g/cm³

|

|-

| &nbsp;75&nbsp;°C || 3711 kPa

| 0.51626 g/cm³ ||

||

|-

| &nbsp;80&nbsp;°C || 4144 kPa

| 0.50571 g/cm³

| 3.41&times;10⁻² g/cm³

|

|-

| &nbsp;85&nbsp;°C || 4614 kPa

| 0.49463 g/cm³ ||

||

|-

| &nbsp;90&nbsp;°C || 5123 kPa

| 0.48290 g/cm³

| 4.39&times;10⁻² g/cm³

|

|-

| &nbsp;95&nbsp;°C || 5672 kPa

| 0.47041 g/cm³ ||

||

|-

| 100&nbsp;°C || 6264 kPa

| 0.45693 g/cm³

| 5.68&times;10⁻² g/cm³

|

|-

|-

| bgcolor="E0E0E0" align="center" | Temp.

| bgcolor="E0E0E0" align="center" | Pressure

| bgcolor="E0E0E0" align="center" | ρ of liquid

| bgcolor="E0E0E0" align="center" | ρ of vapor

| bgcolor="E0E0E0" align="center" | Δ_vapH

|-

| colspan="5" | 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.

|}

| width="4%" | &nbsp; || valign="top" width="36%" |thumb|330px|Freezing curve of ammonia-water system. Three eutectic points I. II. and III. are shown. Left of the I. point the frozen component is ice. Right of the III. point the frozen component is ammonia.

{| border="1" cellspacing="0" cellpadding="6" style="margin: 0 0 0 0.5em; background: white; border-collapse: collapse; border-color: #C0C090;"

! colspan="4" | Vapor over aqueous ammonia solution

|-

| bgcolor="E0E0E0" align="center" | Temp.

| bgcolor="E0E0E0" align="center" | %wt NH₃

| bgcolor="E0E0E0" align="center" | Partial pressure<br>NH₃

| bgcolor="E0E0E0" align="center" | Partial pressure<br>H₂O

|-

| rowspan="5" | 0&nbsp;°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

|-

| rowspan="6" | 10&nbsp;°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

|-

| rowspan="9" | 19.9&nbsp;°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

|-

| rowspan="7" | 30.09&nbsp;°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

|-

| rowspan="6" | 40&nbsp;°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

|-

| rowspan="6" | 50&nbsp;°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

|-

| rowspan="5" | 60&nbsp;°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

|-

| bgcolor="E0E0E0" align="center" | Temp.

| bgcolor="E0E0E0" align="center" | %wt NH₃

| bgcolor="E0E0E0" align="center" | Partial Pressure<br>NH₃

| bgcolor="E0E0E0" align="center" | Partial Pressure<br>H₂O

|-

|}

|}

Heat capacity of liquid and vapor

{|

|- valign="top"

| thumb|625px|left|Heat capacity, c_p, of anhydrous ammonia gas. Uses polynomial <!-- <math>\scriptstyle c_p (kJ/mol K) = </math><math>\scriptstyle 34.23600 - 0.02214127(T+273.15) + 1.212511 \times 10^{-4}(T+273.15)^2 - 1.088291 \times 10^{07}(T+273.15)^3 + 3.203149 \times 10^{-11}(T+273.15}</math> --> obtained from CHERIC.

|-

| [[Image:AmmoniaLiquidHeatCapacity.png|thumb|300px|left|Heat capacity of anhydrous liquid ammonia. Uses polynomial obtained from CHERIC.