Chapter 8, Problem 8.63SP

Interpretation Introduction

Interpretation:

Pressure-volume work done and $\Delta E$ for the reaction of ethylene with $HCl$ has to be calculated.

Concept Introduction:

In thermodynamics, a system refers to a macroscopic material made of particles to say in simple words it is composed of certain quantity of matter.  The molecules contained in the substance of a system possesses different types of energy such as potential energy, kinetic energy, translational energy, vibrational energy, rotational energy, electrical energy.  The sum of all of these energy possessed by the matter of the system is termed as internal energy of the system.

Enthalpy corresponds to heat content of the system and it is represented by ‘H’ and it is the sum of internal energy ‘E’ and product of volume and pressure,

$H=E+PV$

$\Delta H$ refers to change in enthalpy.  Since enthalpy corresponds to the heat content of the system, change in enthalpy $\Delta H$ corresponds to change in heat content of the system at constant pressure and hence it is equivalent to $q_p.$  Thus $\Delta H$ is measured at constant pressure.

According to First law of Thermodynamics, work done is given by,

$w=-P\Delta V$

Where,

$\begin{array}{l}P=\text{ pressu}re\\ \Delta V=\text{ change in volume}\end{array}$