Ammonia - Thermophysical Properties (original) (raw)

Ammonia is a colourless gas with a characteristic pungent smell and hazardous in its concentrated form.

Chemical, physical and thermal properties of Ammonia, NH3 :
Values at 25 oC /77 oF / 298 K and 1 atm., if not other temperature and pressure given.
If values are given for liquid ammonia at ambient temperature, the ammonia is pressurized above 1 atm.

For full table with Imperial units - rotate the screen!

Ammonia - Thermophysical Properties

Property Value Unit Value Unit Value Unit Value Unit
Acidity (pKa) 9.24
Acidity (pKa) at -33°C 32.5
Autoignition point 903 K 630 °C 1166 °F
Basicity (pKb) 4.75
Boiling point 239.82 K -33.33 °C -27.99 °F
Critical density 14327 mol/m3 243.99 kg/m3 15.23 lb/ft3 0.4734 slug/ft3
Critical pressure 11.357 MPa=MN/m2 113.57 bar 112.08 atm 1647.2 psi=lbf/in2
Critical temperature 405.56 K 132.41 °C 270.34 °F
Critical volume 69.8 cm3 /mol 0.00410 m3 /kg 0.0657 ft3 /lb 2.11 ft3 /slug
Density , gas 41.1 mol/m3 0.699 kg/m3 0.0437 lb/ft3 0.00136 slug/ft3
Density, liquid at -28 °F/-33.35°C, 1 atm 40868 mol/m3 696 kg/m3 43.4 lb/ft3 1.35 slug/ft3
Density, liquid at 70 °F/21.1°C 36259 mol/m3 617.5 kg/m3 38.55 lb/ft3 1.198 slug/ft3
Flammable no
Flash point 405 K 132 °C 269 °F
Gas constant , R 488.2 J/kg K 0.1356 Wh/(kg K) 90.74 ft lbf /lb °R 2919 ft lbf /slug °R
Gibbs free energy of formation, ΔGf -16.6 kJ/mol -975 kJ/kg -0.42 Btu/lb
Heat (enthalpy) of combustion , ΔHc (gas) 382.8 kJ/mol 22477 kJ/kg 9.663 Btu/lb
Heat (enthalpy) of evaporation , ΔHv, at boiling point 23.37 kJ/mol 1372.0 kJ/kg 589.87 Btu/lb
Heat(enthalpy) of formation , ΔHf (gas) -45.9 kJ/mol -2695 kJ/kg -1.16 Btu/lb
Heat (enthalpy) of fusion/melting, ΔHm 5.653 kJ/mol 332.3 kJ/kg 143 Btu/lb
Heat (enthalpy) of sublimation, ΔHS , at 180 K 31.2 kJ/mol 1832 kJ/kg 0.79 Btu/lb
Ionization potential 10.18 eV
Melting (freezing) point 195.42 K -77.73 °C -107.91 °F
Molecular Weight 17.03052 g/mol 0.03755 lb/mol
pH of 0.01 N aqueous solution 10.6
pH of 0.1 N aqueous solution 11.1
pH of 1.0 N aqueous solution 11.6
Standard molar entropy , S° (gas) at 1 bar 192.77 J/mol K 11.32 kJ/kg K 0.002704 Btu/lb °F
Solubility in water, at 20°C 540 mg/ml
Solubility in water, at 24°C 482 mg/ml
Sound velocity in gas 415 m/s
Specific Gravity , gas (density relativ to air) 0.604
Specific heat (heat capacity), Cp (gas) 37.0 J/mol K 2.175 kJ/kg K 0.5200 Btu/lb°F = cal/g K
Specific heat (heat capacity), Cp (liquid) 80.8 J/mol K 4.744 kJ/kg K 1.133 Btu/lb°F = cal/g K
Specific heat ratio - Cp /Cv (gas) 1.32
Specific volume 0.02435 m3 /mol 1.43 m3 /kg 22.91 ft3 /lb 736.99 ft3 /slug
Surface tension at 11.1°C/52.0°F 23.4 dynes/cm
Surface tension at 34.1°C/93.4°F 18.1 dynes/cm
Thermal Conductivity 0.026 W/m°C 0.015 Btu/hr ft °F
Triple point pressure 0.00609 MPa=MN/m2 0.0609 bar 0.0601 atm 0.883 psi=lbf /in2
Triple point temperature 195.5 K -77.65 °C -107.77 °F
Vapor (saturation) pressure 1.00 MPa=MN/m2 7500 mm Hg 9.869 atm 145.0 psi=lbf /in2
Vapor (saturation) pressure at -49.72°F/-45.4°C 0.0533 MPa=MN/m2 400 mm Hg 0.526 atm 7.73 psi=lbf /in2
Viscosity, dynamic (absolute) (gas) 0.0100 cP 6.72*10-6 lbm/ft s 0.209*10-6 lbf s/ft2
Viscosity, dynamic (absolute) at 27°C (liq) 0.1293 cP 86.89*10-6 lbm/ft s 2.70*10-6 lbf s/ft2
Viscosity, dynamic (absolute) at -33.5°C (liq) 0.255 cP 171.4*10-6 lbm/ft s 5.326*10-6 lbf s/ft2

See also the following documents for changes in ammonia properties with changes in pressure and temperature:

See also more about atmospheric pressure , and STP - Standard Temperature and Pressure & NTP - Normal Temperature and Pressure ,
as well as Thermophysical properties of: Acetone , Acetylene , Air , Argon , Benzene , Butane , Carbon dioxide , Carbon monoxide , Ethane , Ethanol , Ethylene , Helium , Hydrogen , Hydrogen sulfide , Methane , Methanol , Nitrogen , Oxygen , Pentane , Propane , Toluene , Water and Heavy water, D2O .

Ammonia is a gas at standard conditions. However, at low temperature and/or high pressures the gas becomes a liquid. The phase diagram for ammonia shows the phase behavior with changes in temperature and pressure. The curve between the triple point and the critical point shows the ammonia boiling point with changes in pressure.

Below the triple point temperature, ammonia becomes a solid, this phase will also be present at very high pressure (> 10 000 bar) and ambient temperature.

/Ammonia phase diagram C

At the critical point there is no change of state when pressure is increased or if heat is added.

The triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium.

Solubility of Ammonia in Water

Ammonia NH3 Solubility in Water vs. Pressure and Temperature

Chemical, physical and thermal properties of acetone, also called 2-propanone, dimethyl ketone and pyroacetic acid. Phase diagram included.

Thermal properties of air at different temperatures - density, viscosity, critical temperature and pressure, triple point, enthalpi and entropi, thermal conductivity and diffusivity and more.

Online calculator, figures and tables showing dynamic (absolute) and kinematic viscosity of gasous and liquid ammonia at temperatures ranging from -73 to 425°C (-100 to 800°F) at pressure ranging from 1 to 1000 bara (14.5 - 14500 psia) - SI and Imperial Units.

Ammonia and health symptoms - smell and threat to life.

Thermodynamic properties of saturated and superheated ammonia R-717 like specific volume, enthalpy and entropy.

Figures and table with changes in Prandtl number for ammonia with changes in temperature and pressure.

Figures and tables showing how the properties of liquid and gaseous ammonia changes along the boiling/condensation curve (temperature and pressure between triple point and critical point conditions). An ammonia phase diagram are included.

Online calculator, figures and tables showing specific heat, CP and CV, of gasous and liquid ammonia at temperatures ranging from -73 to 425°C (-100 to 800°F) at pressure ranging from 1 to 100 bara (14.5 - 1450 psia) - SI and Imperial Units.

Online calculator, figures and tables showing thermal conductivity of liquid and gaseous ammonia at temperatures ranging -70 to 425 °C (-100 to 800 °F) at atmospheric and higher pressure - Imperial and SI Units.

Figures and table with ammonia saturation pressure at boiling points, SI and Imperial units.

Online calculator with figures and tables showing density and specific weight of ammonia for temperatures ranging -50 to 425 °C (-50 to 800 °F) at atmospheric and higher pressure - Imperial and SI Units.

Chemical, physical and thermal properties of benzene, also called benzol. Phase diagram included.

Chemical, physical and thermal properties of carbon dioxide. Phase diagram included.

Critical temperatures and pressures for some common substances like air, alcohol, ether, oxygen and more.

Chemical, Physical and Thermal Properties of Ethane - C2H6.

Chemical, physical and thermal properties of ethylene, also called ethene, acetene and olefiant gas. Phase diagram included.

Thermodynamic properties of heavy water (D2O) like density, melting temperature, boiling temperature, latent heat of fusion, latent heat of evaporation, critical temperature and more.

Density, specific heat, thermal conductivity, viscosity and Prandtls no. of liquid ammonia at saturation pressure.

Specific heats for some common liquids and fluids - acetone, oil, paraffin, water and many more.

Chemical, Physical and Thermal Properties of Methane - CH4. Phase diagram included.

Chemical, physical and thermal properties of methanol, CH3OH (also called carbinol, wood alcohol, hydroxy methyl and methyl alcohol). Phase diagram included.

Chemical, physical and thermal properties of pentane, also called n-pentane. Phase diagram included.

Solubility of Ammonia, Argon, Carbon Dioxide, Carbon Monoxide, Chlorine, Ethane, Ethylene, Helium, Hydrogen, Hydrogen Sulfide, Methane, Nitrogen, Oxygen and Sulfur Dioxide in water.

Thermal properties of water at different temperatures like density, freezing temperature, boiling temperature, latent heat of melting, latent heat of evaporation, critical temperature and more.