Chapter 21, Problem 21.20QP

Interpretation Introduction

Interpretation: The effects of chlorofluorocarbon compound substitutes should be identified.

Concept Introduction:

Atmosphere: The atmosphere is defined as air that is layer of gases which surrounds the earth due to gravity of earth.

The earth atmosphere consists of layers such as thermosphere, mesosphere, stratosphere and troposphere depending on the temperature and its composition.

Stratosphere:

It is found below the mesosphere layer in which the concentration of ozone and other gases are high. The increasing temperature for this layer with respect to increasing height is due to the presence of high concentration of ozone and other gases in it.

The increased temperature is due to the response of UV radiation from sun and hence ozone is formed due to this reaction and the use of ozone is that it prevents the UV radiation from the sun which is actually harmful.

Troposphere:

The layer is below stratosphere layer and it is closest to the earth surface. It is wholly composed of major air that is 80% of the total mass and almost all the water vapor.

It is the thinnest place which is responsible for all weather conditions since it contains almost all amounts of water vapor with it.

Chlorofluorocarbon (CFC): They are compounds that contain only carbon, fluorine and chlorine with it. They are gases can be easily liquefied, have little ability to react readily, are non-poisonous and do not catch fire easily.

CFC substitutes: They are compounds that replace the CFC in order to control the ill effects of CFC towards ozone depletion. The example of such substitutes is as follows, ${\text{CF}}_{\text{3}}{\text{CFH}}_{\text{2}}{\text{,CF}}_{\text{3}}{\text{CF}}_{\text{2}}{\text{H,CF}}_{\text{3}}{\text{CH}}_{\text{3}}{\text{ and CF}}_{\text{2}}{\text{HCH}}_{\text{3}}$

To determine: The effects for substitutes of CFC in earth atmosphere should be explained.