Chapter 19, Problem 133A

Interpretation Introduction

Interpretation : The kilojoules of energy are to be calculated.

Concept Introduction : A substance's specific heat capacity is the amount of energy required to raise its temperature by one degree Celsius. The formula to calculate the heat is given as

  $\text{q = mcΔT}$

Here, $\text{m}$ is the mass, $\text{c}$ is the specific heat capacity and $\text{ΔT}$ is the change in temperature.

Answer to Problem 133A

The kilojoules of energy are $\text{2}\text{.8}\text{kJ}$ .

Explanation of Solution

A substance's heat capacity is determined by the relationship between the amount of energy applied to it and the resulting rise in temperature.

The specific heat capacity of iron is $0.46\text{J/}\left({\text{g}}^{\text{o}}\text{C}\right)$ .

Mass of iron is $432\text{g}$ .

The rise in temperature is ${14}^{\circ }\text{C}$ .

The formula to calculate the heat is given as

  $\text{q = mcΔT}$

Here, $\text{m}$ is the mass, $\text{c}$ is the specific heat capacity and $\text{ΔT}$ is the change in temperature.

To calculate the energy in kilojoules, substitute the values in above formula:

  $\begin{array}{c}\text{q = mcΔT}\\ \text{=}432\text{g}\times 0.46\text{J/}\left({\text{g}}^{\text{o}}\text{C}\right)\times {14}^{\circ }\text{C}\\ =2782.08\text{J}\\ \text{=}\text{2}\text{.8}\text{kJ}\end{array}$