<P> The term endothermic process describes the process or reaction in which the system absorbs energy from its surroundings , usually in the form of heat . The term was coined by Marcellin Berthelot from the Greek roots endo - , derived from the word `` endon '' ( ἔνδον ) meaning `` within '' and the root `` therm '' ( θερμ - ) meaning `` hot '' or `` warm '' intended sense is that of a reaction that depends on absorbing heat if it is to proceed . The opposite of an endothermic process is an exothermic process , one that releases , `` gives out '' energy in the form of heat . Thus in each term ( endothermic & exothermic ) the prefix refers to where heat goes as the reaction occurs , though in reality it only refers to where the energy goes , without necessarily being in the form of heat . All chemical reactions involve both the breaking of existing and the making of new chemical bonds . A reaction to break a bond always requires the input of energy and so such a process is always endothermic . When atoms come together to form new chemical bonds , the electrostatic forces bringing them together leave the bond with a large excess of energy ( usually in the form of vibrations and rotations ) . If that energy is not dissipated , the new bond would quickly break apart again . Instead , the new bond can shed its excess energy - by radiation , by transfer to other motions in the molecule , or to other molecules through collisions - and then become a stable new bond . Shedding this excess energy is the exothermicity that leaves the molecular system . Whether a given overall reaction is exothermic or endothermic is determined by the relative contribution of these bond breaking endothermic steps and new bond stabilizing exothermic steps . </P>
<P> The term endothermic process describes the process or reaction in which the system absorbs energy from its surroundings , usually in the form of heat . The term was coined by Marcellin Berthelot from the Greek roots endo - , derived from the word `` endon '' ( ἔνδον ) meaning `` within '' and the root `` therm '' ( θερμ - ) meaning `` hot '' or `` warm '' intended sense is that of a reaction that depends on absorbing heat if it is to proceed . The opposite of an endothermic process is an exothermic process , one that releases , `` gives out '' energy in the form of heat . Thus in each term ( endothermic & exothermic ) the prefix refers to where heat goes as the reaction occurs , though in reality it only refers to where the energy goes , without necessarily being in the form of heat . All chemical reactions involve both the breaking of existing and the making of new chemical bonds . A reaction to break a bond always requires the input of energy and so such a process is always endothermic . When atoms come together to form new chemical bonds , the electrostatic forces bringing them together leave the bond with a large excess of energy ( usually in the form of vibrations and rotations ) . If that energy is not dissipated , the new bond would quickly break apart again . Instead , the new bond can shed its excess energy - by radiation , by transfer to other motions in the molecule , or to other molecules through collisions - and then become a stable new bond . Shedding this excess energy is the exothermicity that leaves the molecular system . Whether a given overall reaction is exothermic or endothermic is determined by the relative contribution of these bond breaking endothermic steps and new bond stabilizing exothermic steps . </P>
where does the energy in endothermic reactions come from
where does the energy in endothermic reactions come from
from its surroundings , usually in the form of heat
from its surroundings , usually in the form of heat