Chemical, physical and thermal properties of ammonia. Phase diagram included.
The ammonia It is a characteristic and dangerous powerless colorless gas in its concentrated form.
Chemical, physical and thermal properties of ammonia, NH 3 :
Values at 25 o C /77 o F / 298 k and 1 atm. If no other temperatures and pressures are indicated. If the values are supplied to liquid ammonia at room temperature, ammonia is pressurized above 1 atm.
| Property | Valor | Unit | Valor | Unit | Valor | Unit | Valor | Unit | |||
| Acidity (PKA) | 9,24 | ||||||||||
| Acidity (PKA) to -33 ° C | 32,5 | ||||||||||
| Automatic ignition 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/whate 3 | 0,4734 | SLESMA/FOOT 3 | |||
| Critical pressure | 11.357 | MPa = MN/ M2 | 113,57 | bar | 112,08 | ATM | 1647,2 | psi = lbf/pol 2 | |||
| Critical temperature | 405,56 | K | 132,41 | °C | 270,34 | °F | |||||
| Critical volume | 69,8 | cm3 / mol | 0,00410 | M3 / kg | 0,0657 | feet 3 /lb | 2.11 | feet 3 /slug | |||
| density, gas | 41.1 | mol / M3 | 0,699 | kg/ M3 | 0,0437 | lb/whate 3 | 0,00136 | SLESMA/FOOT 3 | |||
| Density, liquid to -28 ° f/-33.35 ° C, 1 atm | 40868 | mol / M3 | 696 | kg/ M3 | 43,4 | lb/whate 3 | 1,35 | SLESMA/FOOT 3 | |||
| Density, liquid at 70 ° F/21.1 ° C | 36259 | mol / M3 | 617,5 | kg/ M3 | 38,55 | lb/whate 3 | 1.198 | SLESMA/FOOT 3 | |||
| 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 lb f /lb °R | 2919 | ft lb f /slug °R | |||
| Gibbs Free Energy, ΔG f | -16,6 | kJ/mol | -975 | kJ/kg | -0,42 | Btu/lb | |||||
| Combustion heat (enthalpy), ΔH c (gas) | 382,8 | kJ/mol | 22477 | kJ/kg | 9.663 | Btu/lb | |||||
| Heat (enthalpy) of evaporation, ΔH v , at the boiling point | 23,37 | kJ/mol | 1372,0 | kJ/kg | 589,87 | Btu/lb | |||||
| Heat (enthalpy) of formation, ΔH f (gas) | -45,9 | kJ/mol | -2695 | kJ/kg | -1,16 | Btu/lb | |||||
| Heat (enthalpy) fusion/melting, ΔH m | 5.653 | kJ/mol | 332,3 | kJ/kg | 143 | Btu/lb | |||||
| Heat (enthalpy) of sublimation, ΔH S , a 180 K | 31.2 | kJ/mol | 1832 | kJ/kg | 0,79 | Btu/lb | |||||
| Ionization potential | 18/10 | eV | |||||||||
| Melting point (freezing) | 195,42 | K | -77,73 | °C | -107,91 | °F | |||||
| Molecular weight | 17.03052 | g/mol | 0,03755 | lb/mol | |||||||
| aqueous solution pH 0.01 n | 10,6 | ||||||||||
| 0.1 n aqueous solution pH | 11.1 | ||||||||||
| pH of 1.0 n aqueous solution | 11.6 | ||||||||||
| Standard molar entropy, s ° (gas) to 1 bar | 192,77 | J/mol k | 11.32 | kJ/kg K | 0,002704 | Btu/lb °F | |||||
| Water solubility, at 20 ° C | 540 | mg/ml | |||||||||
| Water solubility, at 24 ° C | 482 | mg/ml | |||||||||
| Gas Sound Speed | 415 | EM | |||||||||
| Specific gravity, gas (air density) | 0,604 | ||||||||||
| Specific heat (thermal capacity), CP (gas) | 37,0 | J/mol k | 2.175 | kJ/kg K | 0,5200 | Btu/lb°F = cal/g K |
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| Specific heat (thermal capacity), CP (liquid) | 80,8 | J/mol k | 4.744 | kJ/kg K | 1.133 | Btu/lb°F = cal/g K |
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| Specific heat ratio - C p /C v (gas) | 1,32 | ||||||||||
| Specific volume | 0,02435 | M3 / mol | 1,43 | M3 / kg | 22.91 | feet 3 /lb | 736,99 | feet 3 /slug | |||
| Surface tension at 11.1 ° C/52.0 ° F | 23,4 | Dinas/CM | |||||||||
| Surface tension at 34.1 ° C/93.4 ° F | 18.1 | Dinas/CM | |||||||||
| Thermal conductivity | 0,026 | A/m°C | 0,015 | Btu/h ft °F | |||||||
| Triple point pressure | 0,00609 | MPa = MN/ M2 | 0,0609 | bar | 0,0601 | ATM | 0,883 | psi = lb f /in 2 | |||
| Triple point temperature | 195,5 | K | -77,65 | °C | -107,77 | °F | |||||
| Steam pressure (saturation) | 1,00 | MPa = MN/ M2 | 7500 | mm Hg | 9.869 | ATM | 145,0 | psi = lb f /in 2 | |||
| Vapor pressure (saturation) to -49.72 ° f/-45.4 ° C | 0,0533 | MPa = MN/ M2 | 400 | mm Hg | 0,526 | ATM | 7,73 | psi = lb f /in 2 | |||
| Viscosity, dynamics (absolute) (gas) | 0,0100 | cP | 6,72*10-6 | LBM/Pés | 0,209*10-6 | lbf s /late 2 | |||||
| Viscosity, dynamic (absolute) to 27 ° C (LIQ) | 0,1293 | cP | 86,89*10-6 | LBM/Pés | 2,70*10-6 | lbf s /late 2 | |||||
| Viscosity, dynamic (absolute) to -33.5 ° C (LIQ) | 0,255 | cP | 171,4*10-6 | LBM/Pés | 5,326*10-6 | lbf s /late 2 |
Ammonia is a gas under standard conditions. However, at low temperatures and/or high pressures the gas becomes a liquid. The phase diagram for ammonia shows the behavior of the phases with temperature and pressure changes. The curve between the triple point and the critical point shows the boiling point of ammonia with changes in pressure.
Abaixo da temperatura do ponto triplo, a amônia se torna sólida, esta fase também estará presente em pressão muito alta (> 10.000 bar) e temperatura ambiente.
No critical point There is no state change when pressure is increased or if heat is added.
O triple of a substance is the temperature and pressure in which the three phases (gas, liquid and solid) of this substance coexist in thermodynamic balance.
Source: https://www.engineeringtoolbox.com/ammonia-d_1413.html
