Chapter 14.3, Problem 35LC

Interpretation Introduction

Interpretation: Ammonia condenses at $-{33.3}^{\circ }\text{C}$ , but nitrogen does not until the temperature reaches $-{195.79}^{\circ }\text{C}$ is to be explained.

Concept Introduction: The electronegativity of the atoms involved determines the bond polarity. The bond polarity is increased by large differences between the electronegativity of the atoms that are bonded.

Answer to Problem 35LC

Ammonia is polar, while nitrogen is a nonpolar molecule. Ammonia condenses at $-{33.3}^{\circ }\text{C}$ , but nitrogen does not until the temperature reaches $-{195.79}^{\circ }\text{C}$ due to the difference in the bond polarity.

Explanation of Solution

The ammonia condenses at $-{33.3}^{\circ }\text{C}$ , but nitrogen does not until the temperature reaches $-{195.79}^{\circ }\text{C}$ . Due to differences in bond polarity, ammonia condenses at a higher temperature than nitrogen at standard pressure.

The molecules of nitrogen are nonpolar and lack intermolecular attraction. In contrast, ammonia molecules are polar and exhibit intermolecular attraction. More polar molecules will attach more strongly to one another and condense faster than less polar molecules.

Conclusion

Ammonia is polar, while nitrogen is a nonpolar molecule. Ammonia condenses at $-{33.3}^{\circ }\text{C}$ , but nitrogen does not until the temperature reaches $-{195.79}^{\circ }\text{C}$ due to the difference in the bond polarity.