Standard enthalpy change of vaporization

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The standard enthalpy change of vaporization is a physical property of substances. It is defined as the amount of heat (or energy) required per unit mass of a substance to completely vaporize the substance at its boiling point. The heat of vaporization is expressed in kJ/mol, or calories/gram. The use of kJ/kg is also possible, but less customary. Other units still in use in certain places include Btu/lb.

Because vaporization is the opposite process of condensation, the term heat of condensation is also used. The latter is defined as the heat released when a unit mass of a substance is completely condensed at its boiling point.

The standard enthalpy change of vaporization of water is about 2260 kJ/kg which is equal to 40.8 kJ/mol. This is quite a lot: it is five times the energy needed for heating the same mass of water from 0 °C to 100 °C.

Heats of vaporization of the

Element Heat of vaporization (kJ/mol) Actinium n/a Aluminium 293.4 Antimony 77.14 Argon 6.447 Arsenic 34.76 Astatine 114 Barium 142 Beryllium 292.40 Bismuth 104.8 Boron 489.7 Bromine 15.438 Cadmium 100 Caesium 67.74 Calcium 153.6 Carbon 355.8 Cerium 414 Chlorine 10.2 Chromium 344.3 Cobalt 376.5 Copper 300.3 Fluorine 3.2698 Gallium 258.7 Germanium 330.9 Gold 334.4 Hafnium 575 Helium 0.0845

Element Heat of vaporization (kJ/mol) Hydrogen 0.44936 Indium 231.5 Iodine 20.752 Iridium 604 Iron 349.6 Krypton 9.029 Lanthanum 414 Lead 177.7 Lithium 145.92 Magnesium 127.4 Manganese 226 Mercury 59.229 Molybdenum 598 Neon 1.7326 Neptunium n/a Nickel 370.4 Niobium 696.6 Nitrogen 2.7928 Osmium 627.6 Oxygen 3.4099 Palladium 357 Phosphorus 12.129 Platinum 510 Polonium 60.1 Potassium 79.87 Radium 37

Element Heat of vaporization (kJ/mol) Radon 16.4 Rhenium 715 Rhodium 493 Rubidium 72.216 Ruthenium 595 Scandium 314.2 Selenium 26.3 Silicon 384.22 Silver 250.58 Sodium 96.96 Strontium 144 Sulfur 1.7175 Tantalum 743 Technetium 660 Tellurium 52.55 Terbium ??? Thallium 164.1 Thorium 514.4 Tin 295.8 Titanium 421 Tungsten 824 Vanadium 452 Xenon 12.636 Yttrium 363 Zinc 115.3 Zirconium 58.2

Other common substances

Element Heat of vaporization (kJ/mol) Methanol 37.4 Ammonia 23.35 Water 40.65 Methane 8.19 Phosphine 14.6 Propane 356 kJ/kg Butane 362 kJ/kg See also Standard enthalpy change of fusion Reference Sears, Zemansky et. al., University Physics, Addison-Wessley Publishing Company, Sixth ed., 1982, ISBN 0-201-07199-1   From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating. All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details. Search Titles 0 1 2 3 4 5 6 7 8 9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ? E-mail this article to: Personal Message: