CFC Chlorofluorocarbon Properties & Environmental Impact 3

Question 1

The Montreal Protocol was signed in 1987 primarily to address which environmental problem?

Accepted Answer

Stratospheric ozone depletion by CFCs and halons

Answer

The Montreal Protocol on Substances that Deplete the Ozone Layer was negotiated in response to scientific evidence that CFCs and halons were destroying the stratospheric ozone layer.

Question 2

R-12, one of the most widely used CFCs, has the chemical formula:

Accepted Answer

CCl₂F₂

Answer

R-12 (dichlorodifluoromethane) has the formula CCl₂F₂, featuring two chlorine atoms and two fluorine atoms on a single carbon, giving it high stability and ODP of 1.0.

Question 3

In the context of CFC refrigerants, what does the term 'critical temperature' refer to?

Accepted Answer

The temperature above which the refrigerant cannot exist as a liquid regardless of pressure

Answer

Critical temperature is the temperature above which a substance cannot be liquefied by pressure alone, which determines the operating limits of refrigeration systems using that refrigerant.

Question 4

Which CFC compound was widely used as a blowing agent in foam insulation before being phased out?

Accepted Answer

R-11 (CFC-11)

Answer

CFC-11 (trichlorofluoromethane) was extensively used as a blowing agent for rigid polyurethane foam insulation due to its low boiling point and insulating properties.

Question 5

What is the approximate atmospheric lifetime of CFC-12 (R-12)?

Accepted Answer

100 years

Answer

CFC-12 has an atmospheric lifetime of approximately 100 years, meaning emissions today will continue depleting the ozone layer for a century.

(CFC) Chlorofluorocarbon Certification Practice Test

(CFC) Chlorofluorocarbon Certification Practice Test

CFC Chlorofluorocarbon Properties & Environmental Impact 3