Chapter U5.5, Problem 4E

Interpretation Introduction

Interpretation: The substance which would be hottest and coolest to the touch, if same amount of the energy is transferred to all the substance needs to be determined.

Concept Introduction: Due to transfer of energy, the temperature of any substance increases or decreases. The change in temperature for the addition of energy can be calculated with the help of following equation:

  $\begin{array}{l}\text{Q = m × C × ΔT}\\ \text{Here:}\\ \text{Q}\text{}\text{ = heat change }\\ \text{m = mass}\\ \text{C = specific heat }\\ \text{ΔT=change in T}\end{array}$

Answer to Problem 4E

In the given substances, copper has least specific heat therefore it would be hottest to the touch whereas hydrogen would be coolest as it has highest specific heat so it will need more energy to raise its temperature.

Explanation of Solution

Specific heat can be defined as the heat that would require raising the temperature of 1 unit mass by per °C. Thus, the substance with highest specific heat would require the most energy to increase the temperature.

If same energy is transferred to the same mass of the substances, then the substance with least specific heat would have highest final temperature.

In the given substances, copper has least specific heat that is 0.09 cal/g ^oC therefore it would be hottest to the touch whereas hydrogen would be coolest as it has highest specific heat that is 3.34 cal/g ^oC so it will need more energy to raise its temperature.

Conclusion

If same energy is transferred to the same mass of the substances, then the substance with least specific heat would have highest final temperature.