Chapter 18, Problem 134A

Interpretation Introduction

Interpretation: The amount of heat released when 32.8 g of ethene is burned is to be calculated.

Concept Introduction: The measurement of the energy in a thermodynamic system is termed enthalpy.

Answer to Problem 134A

The amount of heat released when 32.8 g of ethene is burned is -1649.9 kJ.

Explanation of Solution

The given chemical equation is represented as:

  ${\text{C}}_{\text{2}}{\text{H}}_{\text{4}}\left(\text{g}\right)+3{\text{O}}_{\text{2}}\left(\text{g}\right)\to {\text{2CO}}_{\text{2}}\left(\text{g}\right)+{\text{2H}}_{\text{2}}\text{O}\left(\text{g}\right)----\Delta \text{H}=-1411\text{kJ}$

According to the reaction, one mole of ethene is burnt. Thus, the amount of heat released during the process is calculated as:

  $\begin{array}{c}\Delta \text{H}=32.8\text{g}{\text{C}}_2{\text{H}}_6\times \frac{\text{1}\text{mol}{\text{C}}_2{\text{H}}_6}{\text{28}\text{.05}\text{g}{\text{C}}_2{\text{H}}_6}\times \frac{\left(-1411\text{kJ}\right)}{\text{1}\text{mol}{\text{C}}_2{\text{H}}_6}\\ \Delta \text{H}=-1649.9\text{kJ}\end{array}$