Chapter 14, Problem 14.70P

Interpretation Introduction

Interpretation:

The reason to use calorimeter to measure heat evolved in reaction rather than thermometer has to be determined.

Concept Introduction:

Thermodynamics is a study of energy transfers that can be done by either heat or work. The energy transferred through work involves force. When work is positive then system gains energy while when work is negative then system loses energy. Since energy as heat is not state function thus it order to find change in energy produced or evolved, change in enthalpy of reaction $\Delta H{°}_{\text{rxn}}$ as a state function has been introduced. The expression to calculate $\Delta H{°}_{\text{rxn}}$ is as follows:

  $\Delta H_{\text{rxn}}=H_{\text{prod}}-H_{\text{react}}$

The useful property of $\Delta H{°}_{\text{rxn}}$ is that it is an additive property.