Chemical, Physical and Thermal Properties of Ammonia. Phase diagram included.
the ammonia It is a colorless gas with a characteristic pungent and dangerous odor 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 other temperatures and pressures are not indicated. If the values are given for liquid ammonia at room temperature, the ammonia is pressurized above 1 atm.
| Property | Valor | Unit | Valor | Unit | Valor | Unit | Valor | Unit | |||
| Acidity (pKa) | 9,24 | ||||||||||
| Acidity (pKa) at -33°C | 32,5 | ||||||||||
| automatic ignition point | 903 | iso-15552-srie-ke | 630 | °C | 1166 | °F | |||||
| Basicidade (pKb) | 4,75 | ||||||||||
| Boiling point | 239,82 | iso-15552-srie-ke | -33,33 | °C | -27,99 | °F | |||||
| critical density | 14327 | mol / m3 | 243,99 | kg/ m3 | 15,23 | lb/ft 3 | 0,4734 | slug/foot 3 | |||
| critical pressure | 11.357 | MPa=MN/ m2 | 113,57 | bar | 112,08 | cash machine | 1647,2 | psi = lbf/pol 2 | |||
| Critical temperature | 405,56 | iso-15552-srie-ke | 132,41 | °C | 270,34 | °F | |||||
| critical volume | 69,8 | cm3 / mol | 0,00410 | m3 / kg | 0,0657 | foot 3 /lb | 2.11 | foot 3 /slug | |||
| density , gas | 41.1 | mol / m3 | 0,699 | kg/ m3 | 0,0437 | lb/ft 3 | 0,00136 | slug/foot 3 | |||
| Density, liquid at -28°F/-33.35°C, 1 atm | 40868 | mol / m3 | 696 | kg/ m3 | 43,4 | lb/ft 3 | 1,35 | slug/foot 3 | |||
| Density, liquid at 70°F/21.1°C | 36259 | mol / m3 | 617,5 | kg/ m3 | 38,55 | lb/ft 3 | 1.198 | slug/foot 3 | |||
| Flammable | no | ||||||||||
| Flash point | 405 | iso-15552-srie-ke | 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 | |||
| Free energy of Gibbs formation, ΔG f | -16,6 | kJ/mol | -975 | kJ/kg | -0,42 | Btu/lb | |||||
| Heat (enthalpy) of combustion, 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) of fusion/fusion, 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 | iso-15552-srie-ke | -77,73 | °C | -107,91 | °F | |||||
| Molecular weight | 17.03052 | g/mol | 0,03755 | lb/mol | |||||||
| pH of aqueous solution 0.01 N | 10,6 | ||||||||||
| pH of aqueous solution 0.1 N | 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 | |||||||||
| speed of sound in gas | 415 | EM | |||||||||
| Specific Gravity, gas (density relative to air) | 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 | foot 3 /lb | 736,99 | foot 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 | cash machine | 0,883 | psi = lb f /in 2 | |||
| triple point temperature | 195,5 | iso-15552-srie-ke | -77,65 | °C | -107,77 | °F | |||||
| Vapor pressure (saturation) | 1,00 | MPa=MN/ m2 | 7500 | mm Hg | 9.869 | cash machine | 145,0 | psi = lb f /in 2 | |||
| Vapor pressure (saturation) at -49.72°F/-45.4°C | 0,0533 | MPa=MN/ m2 | 400 | mm Hg | 0,526 | cash machine | 7,73 | psi = lb f /in 2 | |||
| Viscosity, dynamic (absolute) (gas) | 0,0100 | cP | 6,72*10-6 | lbm/pes | 0,209*10-6 | lbf s /late 2 | |||||
| Viscosity, dynamic (absolute) at 27°C (liq) | 0,1293 | cP | 86,89*10-6 | lbm/pes | 2,70*10-6 | lbf s /late 2 | |||||
| Viscosity, dynamic (absolute) at -33.5°C (liq) | 0,255 | cP | 171,4*10-6 | lbm/pes | 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 phase behavior with changes in temperature and pressure. The curve between the triple point and the critical point shows the boiling point of ammonia with changes in pressure.
Below the triple point temperature, ammonia becomes solid, this phase will also be present at very high pressure (> 10,000 bar) and ambient temperature.
No critical point there is no change of state when pressure is increased or heat is added.
THE triple stitch of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium.
Source: https://www.engineeringtoolbox.com/ammonia-d_1413.html
