Chapter 10, Problem 2A

Interpretation Introduction

Interpretation: The reason for al the energy to not be available for work needs to be determined.

Concept introduction: Energy is defined as the ability to do work or to produce heat. Energy is classified as kinetic energy and potential energy.

Answer to Problem 2A

All the energy is not available for work,because some of the energy is lost in the form of heat.

Explanation of Solution

For a process which is carried out at constant pressure, the changes in enthalpy is equal to the heat. On reversing the reaction, the sign of $\Delta H$ also gets reversed. The magnitude of $\Delta H$ is directly proportional to the quantities of reactants and products in a reaction.

All the energy is not available for work. It is because, some of the energy is lost in the form of heat in this process. An example of this is friction.

Conclusion

Energy is defined as the ability to do work or to produce heat.Not all the energy is available for work, because some of the energy is lost in the form of heat.