Chemistry Homework

1. Using a thermodynamic argument, explain why it is not possible to transfer heat from a body of lower temperature to another body of higher temperature.

 

2. The reaction between H2 and O2 to form water is exothermic. However, in this reaction all H-H and O=O bonds must be broken. Where does the energy required to accomplish this come from? Also comment on the relative changes in the potential and kinetics energies of this system.

 

3. Consider dissolution of NH4Cl(s) in water: NH4Cl(s) = NH4+(aq) + Cl(aq), a process carried out in a closed, thermally insulated container. Knowing that this reaction is endothermic, explain what happens to the heat that was absorbed. As the reaction progresses to the right, do you expect the temperature of the reaction mixture to go up, go down, or stay the same? Explain your reasoning.

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