A flameless ration heater (FRH)

FRH is an abbreviation for "flameless ration heater," a water-activated exothermic chemical heater included with Meals, Ready-to-Eat (MREs), used to heat the food. US military specifications for the heater require that it be capable of raising the temperature of an eight-ounce entree by 100°F in twelve minutes, and that it display no visible flame. Image File history File links Size of this preview: 294 × 598 pixel Image in higher resolution (711 × 1447 pixel, file size: 632 KB, MIME type: image/jpeg) A flameless ration heater (w:FRH) included with the MRE in Image:MRE contents. ... Image File history File links Size of this preview: 294 × 598 pixel Image in higher resolution (711 × 1447 pixel, file size: 632 KB, MIME type: image/jpeg) A flameless ration heater (w:FRH) included with the MRE in Image:MRE contents. ... In chemistry, an exothermic reaction is one that releases heat . ... An MRE packet, containing a main course or entrée of spaghetti with meat sauce. ... The armed forces of the United States of America consist of the United States Army United States Navy United States Air Force United States Marine Corps United States Coast Guard Note: The United States Coast Guard has both military and law enforcement functions. ... Fig. ... Conflagration redirects here. ...

The exothermic chemical reaction works by the process of oxidation-reduction, which is much similar to the process of rusting metals. When iron metal rusts, it is oxidized by the oxygen present in the air. In the case of the flameless ration heater, the metal used is magnesium. Magnesium is chosen because it is readily oxidized, which is due to the fact that it only has two electrons in its valence shell. The magnesium metal is mixed together with a small amount of iron in a pouch. To activate the reaction, a small amount of water is added, and the boiling point of water is quickly reached as the reaction proceeds. The role of iron in the heater is most likely as a catalyst, since it is used in a small amount. In this case, the iron is initially oxidized, and then reduced back to its elemental form as the magnesium is oxidized and sends its two valence electrons to iron [1]. Illustration of a redox reaction Redox (shorthand for oxidation/reduction reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white Atomic mass 24. ... Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ... The valence shell is the outermost shell of an atom, which contains the electrons most likely to account for the nature of any reactions involving the atom and of the bonding interactions it has with other atoms. ... It has been suggested that this article or section be merged into Catalysis. ...

References

• HowStuffWorks article on MREs

See also

• Self-heating can

A self-heating can is an extension of the common food can. ...

External links

• Flameless stoves from zenstoves.net - details chemical reaction