CFC Chlorofluorocarbon Properties & Environmental Impact 5

Question 1

Polar stratospheric clouds (PSCs) accelerate ozone depletion over Antarctica primarily by:

Accepted Answer

Providing surfaces for heterogeneous chemical reactions that activate chlorine

Answer

PSC ice crystal surfaces catalyze reactions that convert reservoir chlorine compounds (like HCl and ClONO₂) into active Cl₂ gas, which rapidly destroys ozone when spring sunlight arrives.

Question 2

The term 'ozone hole' technically refers to:

Accepted Answer

A region where stratospheric ozone falls below 220 Dobson Units

Answer

Scientists define the Antarctic ozone hole as the region where total column ozone drops below 220 Dobson Units (DU), which is substantially lower than the pre-depletion baseline of ~300 DU.

Question 3

R-113 (CFC-113) was primarily used as a(n):

Accepted Answer

Solvent for cleaning electronic circuit boards

Answer

CFC-113 (trichlorotrifluoroethane) was extensively used as a precision cleaning solvent in electronics manufacturing due to its excellent solvency and non-flammability.

Question 4

What does a Dobson Unit (DU) measure in relation to ozone?

Accepted Answer

The total column amount of ozone compressed to standard temperature and pressure

Answer

One Dobson Unit represents a layer of pure ozone 0.01 mm thick at standard temperature and pressure; the total atmospheric ozone column is measured by summing ozone at all altitudes.

Question 5

Which international agreement strengthened the Montreal Protocol by accelerating CFC phase-out schedules for developed nations?

Accepted Answer

Copenhagen Amendment (1992)

Answer

The Copenhagen Amendment of 1992 significantly accelerated CFC phase-out deadlines, moving the complete production ban in developed countries from 2000 to January 1, 1996.

(CFC) Chlorofluorocarbon Certification Practice Test

(CFC) Chlorofluorocarbon Certification Practice Test

CFC Chlorofluorocarbon Properties & Environmental Impact 5