Chapter 10, Problem 9A

Interpretation Introduction

Interpretation: The case in which more heat involved needs to be determined.

Concept introduction: Temperature is the measure of the components random motion. Heat is the flow of energy due to the existence of the temperature difference.

Answer to Problem 9A

More heat is involved in mixing 100.0 g samples of ${\text{90}}^{\text{0}}\text{C}$ water and ${\text{80}}^{\text{0}}\text{C}$ water.

Explanation of Solution

Given two mixtures: mixing 100.0 g samples of ${\text{90}}^{\text{0}}\text{C}$ water and ${\text{80}}^{\text{0}}\text{C}$ water or mixing 100.0 g samples of ${\text{60}}^{\text{0}}\text{C}$ water and ${\text{10}}^{\text{0}}\text{C}$ water.

Here, we have assumed that no heat is lost to the environment.

In the mixture of 100.0 g samples of ${\text{90}}^{\text{0}}\text{C}$ water and ${\text{80}}^{\text{0}}\text{C}$ water, more amount of heat is evolved in comparison to the other mixture. Therefore, more heat is involved in this reaction.

Conclusion

The mixture of 100.0 g samples of ${\text{90}}^{\text{0}}\text{C}$ water and ${\text{80}}^{\text{0}}\text{C}$ water, more heat involved.