Energy Transfer During Endothermic Reaction

Problem The blue substance formed from E10.2 originates from the white copper sulfate and water it contains water of hydration (or crystallization) and is called copper sulfate pentahydrate. Apparently, this blue copper sulfate has a lesser amount of chemical energy than the white copper sulfate (see Fig. 10.3). Adding thermal energy, the blue sulfate can be converted into white sulfate with higher chemical energy. 

Material Test tubes, burner blue copper sulfate (see E10.2). 

Procedure Fix the test tube containing the blue copper sulfate in a slanted position with the opening pointing downward and heat with the hottest burner flame. 

Observation The blue sulfate changes to white sulfate, drops of water condense and drip out of the test tube. As soon as the heat supply is interrupted, the decomposition stops. 

Problem Young people know from experience, that when heating water, each addition of thermal energy leads to an increase in temperature - temperature and heat have the same meaning for many pupils. For this reason, experiments 

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When a gas reacts with a solid, heat will be transfened from the solid to the gas when the reaction is exothermic, and from gas to solid during an endothermic reaction. The energy which is generated will be distributed between the gas and solid phases according to the temperature difference between the two phases, and their respective thermal conductivities. If the surface temperature of the solid is T2 at any given instant, and that of the bulk of the gas phase is Ti, the rate of convective heat transfer from the solid to the gas may be represented by the equation... 

At present, waste heat exhausted from the ICE is removed with any efficient radiator system through direct apparent heat exchanging. On the contrary, organic chemical hydrides can recuperate the chemical energy of endothermic reaction heat during exhausted heat removal. Heat transfers accompanying the phase change of evaporation and condensation of aromatic products and unconverted reactants will certainly facilitate the removal of heat from the ICE parts, with adoption of any new radiator system compelled. 

Mitochondria organize electron transfer and the associated reactions leading to the adenosine triphosphate synthesis called oxidative phosphorylation. Synthesis of adenosine triphosphate is an endothermic reaction, and hence conserves the energy released during biological oxidation-reduction reactions. Electron transfer and associated reactions leading to ATP synthesis are membrane-bound phenomena. NADH and FADH2 are the reduced cofactors of NAD" " and the FAD. The oxidation of one NADH produces approximately three... 

The second process, particle transfer, results in a change of identity of the ion (for example, the ion can be neutralized by electron transfer from the neutral, and an ion of new identity is produced from the neutral). Momentum and energy transfer processes can have a significant inqtact on the outcome of ion-molecule reactions (for example, endothermic reactions discussed in Part 8.1 of Chapter 8 by Koyanagi can potentially be promoted if enough energy is transferred during the collision). 

Work is negative when energy is transferred out of the system and is positive when energy is transferred into the system. This is consistent with the signs associated with the heat of a reaction (q) during exothermic and endothermic processes. 

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