Chapter 8, Problem 8.40SP

Interpretation Introduction

Interpretation:

Work done in a chemical reaction has to be calculated in kilojoules and the sign of energy change has to be described.

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 SI unit of work is joule.