Chapter 21.2, Problem 1PPC

Interpretation Introduction

Interpretation:

From the given molecules, the greenhouse gases are to be determined.

Concept Introduction:

Greenhouse gases absorb and emit infrared radiations in the form of heat. They are like a sheet covering the earth and slows down the rate of heat that escapes off from theEarth’s surface into space. In this way, these gases contribute to global warming.

To qualify as a greenhouse gas, the molecules of the gas must exhibit a dipole moment or some of its vibrational motions must create a dipole moment temporarily. Examples of heteronuclear diatomic molecules or atomic species mostly possess dipole moment.

Dipole moment is represented by $"\mu ."$

Homonuclear molecules or atomic species do not possess any dipole moment. Examples are ${\text{N}}_2,{\text{ Br}}_2,{\text{ F}}_2,\text{Ne, etc}$.

For ${\text{AB}}_{\text{n}}$ types of molecules, where “A” is the central atom, “B” is all the same atoms & “n” is any integer, the molecular geometries are symmetric, and therefore they have no dipole moment even if the bonds are polar. Molecules having the followingmolecular geometries have zero dipolemoment ($\mu =0$) and are nonpolar in nature: Linear geometry, Trigonal planar, Tetrahedral, Octahedral, Trigonal bipyramid.