Chapter 18, Problem 117A

Interpretation Introduction

Interpretation:

The amount of heat released is to be calculated when one mol of compound undergo combustion.

Concept introduction:

Specific heat is defined as quantity of heat required to raise the temperature of one gram substance by one Kelvin. It is represented by ‘c’.

Answer to Problem 117A

The amount of heat released when one mol of compound undergo combustion is $1240kJ$

Explanation of Solution

The quantity of heat required can be calculated by using formula:

$\begin{array}{l}q=mc\Delta T\\ whereqisquantityofheatabsorbed\\ m=givenmass\\ \Delta T=riseintemperature\\ cisspecificheat\end{array}$

Given data:

$\begin{array}{l}{m}_{water}=2Kg=2000g\\ molarmassofcompound=46.1g/mol\\ \Delta T=40.5-24.5\\ =16°C\\ c=4.184J/g-°C\end{array}$

Substituting the values in formula:

$\begin{array}{c}q=2000\times 4.184\times 16\\ =1.34\times {10}^{5}J\\ =1.34\times {10}^{2}kJ\end{array}$

Thus,

$\begin{array}{c}5gsubs\tan ceproduces=1.34\times {10}^{2}kJ\\ 46.1gwillproduce=\frac{1.34\times {10}^2}{5}\times 46.1\\ =1240kJ\end{array}$

Conclusion

Thus,

The amount of heat released when one mol of compound undergo combustion is $1240kJ$