Chapter 6, Problem 6.113SP

Interpretation Introduction

Interpretation:

For the given processes the quantities q, w, $\Delta U$ and $\Delta H$ are positive or negative or zero have to be deduced and the results have to be constructed in a tabular form.

Concept Introduction:

• In thermodynamics Work is defined as transfer of energy from one system to another system or system to surroundings. That is work indicates energy change.  If the change in energy carries positive sign it implies work is done on the system by the surroundings. If the change in energy carries negative sign it implies work is done by the system onto the surroundings.
• According to First law of Thermodynamics, work done is given by,

$w=-P\Delta V$

Where,

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

• The heat content of the system is represented by ‘H’ and it is the sum of internal energy ‘U’ and product of volume and pressure,

$H=E+PV$

•  $\Delta H$ refers to change in enthalpy of the system and $\Delta U$ refers to change in internal energy of the system.  Both are related as,

$\Delta H=\Delta U+P\Delta V$