Chapter 14.2, Problem 5RQ

Interpretation Introduction

Interpretation: The reason for water to boils at ${100}^{\circ }C$ at sea level needs to be explained.

Concept introduction: Boiling involves converting of liquid phase of a substance to its gas phase by supplying heat. It is defined as the temperature at which the pressure of the vapors above the liquid becomes equal to the pressure in the atmosphere also known as the atmospheric pressure. The atmospheric pressure at sea level is 1 atm.

Answer to Problem 5RQ

Water boils at ${100}^{\circ }C$ because the pressure of the water vapors above water becomes equal to the atmospheric pressure at sea level.

Explanation of Solution

Boiling involves converting of liquid phase of a substance to its gas phase by supplying heat. It is defined as the temperature at which the pressure of the vapors above the liquid becomes equal to the pressure in the atmosphere also known as the atmospheric pressure. For water, the vapor pressure equals 1 atm. at temperature equal to ${100}^{\circ }C$ .It is at this temperature that water molecules in liquid phase start getting converted into water vapors.

Conclusion

Water boils at ${100}^{\circ }C$ because the pressure of the water vapors above water becomes equal to the atmospheric pressure at sea level.