Endothermic Reaction


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Endothermic Reaction

 

a chemical reaction that is accompanied by the absorption of heat. Endothermic reactions include dissociation (in particular, the division of molecules into free atoms), photosynthesis in plants, the formation of certain compounds from simple substances, and the process of producing metals from ores by reduction reactions. Endothermic reactions are the reverse of exothermic reactions, during which heat is released.

References in periodicals archive ?
The reasons are as follows: first, a lot of endothermic reaction processes are ignored when adopting the single-step chemical reaction; thus, the temperature and velocity obtained are higher.
Above the combustion zone (4 cm up to the grate), temperature decreases because of the presence of endothermic reactions in the reduction, pyrolysis, and drying zones, with the exception of the shift reaction (CO + [H.sub.2]O [right arrow] C[O.sub.2] + [H.sub.2]).
Increasing pressure during the gelatinization process causes an increase in the peak reaction temperature, or the temperature at which the endothermic reaction occurs at a maximum.
Figure 1 shows that a small decreasing effect of temperature profile is found for increasing values of E for exothermic reaction ([beta] = 1), but mark opposite effects are found for endothermic reaction in Figure 1.
The endothermic reaction occurring in that region is the breakdown of the kaolin molecules releasing water, which is then driven off by the high heat ([Al.sub.2][O.sub.3] x 2Si[O.sub.2] x 2[H.sub.2]O [right arrow] [Al.sub.2][O.sub.3] x 2Si[O.sub.2] + 2[H.sub.2]O).
It is found that the 250 [micro]m particles absorb around -3.4 mW of energy during endothermic reaction and found -4.6 mW for 2057 [micro]m particles.
5 also indicates how the endothermic reaction approaches to equilibrium.
It forms aluminum oxide at 180[degrees]C to 200[degrees]C via an endothermic reaction that absorbs heat from the fire.
Pyrolysis is an endothermic reaction requiring a net input of energy.
It is also an endothermic reaction because it produces heat.
The hydrocracking of DNM is an endothermic reaction, and higher temperature is favorable for the reaction.
Two different thermal behaviors have been found with endothermic reaction occurring in first stage.