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Question

Question: An endothermic reaction proceeds in the forward direction with decrease of temperature. A. True ...

An endothermic reaction proceeds in the forward direction with decrease of temperature.
A. True
B. False

Explanation

Solution

An endothermic process is any process with an increase in the enthalpy H (or internal energy U) of the system. In such a process, a closed system usually absorbs thermal energy from its surroundings, which is the heat transfer into the system. It may be a chemical process, such as dissolving ammonium nitrate in water, or a physical process, such as the melting of ice cubes.

Complete answer:
Whether a reaction can occur spontaneously depends not only on the enthalpy change but also on the entropy change (ΔS\Delta S ) and absolute temperature TT . If a reaction is a spontaneous process at a certain temperature, the products have a lower Gibbs free energy G  =  H    TS  G\; = \;H\; - \;TS\; than the reactants (an exergonic reaction), even if the enthalpy of the products is higher. According to the Le-chatelier’s principle, when the reaction is exothermic (change in enthalpy is negative and energy is released), heat is included as a product, and when the reaction is endothermic (change in enthalpy is positive and energy is consumed), heat is included as a reactant.
Hence, an endothermic reaction proceeds in the backward direction with decrease in temperature as according to the Le-chatelier’s principle, when any system at equilibrium for a long period of time is subjected to a change in concentration, temperature, volume, or pressure, the system changes to a new equilibrium, and this change partly counteracts the applied change.

Thus, the statement is false.

Note:
Thus, an endothermic process usually requires a favorable entropy increase (ΔS  > 0\Delta S\; > {\text{ }}0 ) in the system that overcomes the unfavorable increase in enthalpy so that still ΔG  < 0\Delta G\; < {\text{ }}0 . While endothermic phase transitions into more disordered states of higher entropy, e.g. melting and vaporization, spontaneous chemical reactions at moderate temperatures are rarely endothermic.