EPA 608 Exam Practice 1 – 100 Exam Questions With
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1. Ozone depletion is caused by __________ in HFC refrigerants.
A. Chlorine
B. Fluorine
C. Bromine
D. Hydrogen
Correct Answer: B. Fluorine
Expert Rationale: HFC refrigerants do not contain chlorine, so they do not directly deplete
stratospheric ozone. However, the question as written in the original document appears to contain a
typo — it states "chlorine" as the correct answer, but HFCs (hydrofluorocarbons) contain no chlorine.
The ozone-depleting potential (ODP) of HFCs is zero. CFCs and HCFCs contain chlorine and are the
actual ozone-depleting substances. This question likely intended to ask about CFCs/HCFCs. For exam
purposes, remember: HFCs = no chlorine = no ozone depletion. If the question truly asks about
HFCs, the correct answer is that they do not cause ozone depletion through chlorine. The original
answer key appears erroneous.
2. CFCs and HCFCs __________ making them capable of reaching the stratospheric ozone layer.
A. Dissolve easily in water
B. Do not dissolve in water or easily break down in the atmosphere
C. Are heavier than air
D. React quickly with other chemicals
Correct Answer: B. Do not dissolve in water or easily break down in the atmosphere
Expert Rationale: CFCs and HCFCs are highly stable compounds. Because they do not dissolve in
water (rain cannot wash them out) and do not break down easily in the lower atmosphere, they
persist long enough to migrate to the stratosphere. Once there, UV radiation breaks them apart,
releasing chlorine atoms that destroy ozone.
3. According to the Rowland-Molina theory, __________ are destroyed by each chlorine atom in
the stratosphere.
A. 1,000 ozone molecules
B. 10,000 ozone molecules
,C. 100,000 ozone molecules
D. 1,000,000 ozone molecules
Correct Answer: C. 100,000 ozone molecules
Expert Rationale: The Rowland-Molina hypothesis (1974) proposed that chlorine atoms catalytically
destroy ozone. Each chlorine atom can destroy up to 100,000 ozone molecules before being removed
from the stratosphere. This catalytic cycle is why even small amounts of CFCs can cause significant
ozone depletion.
4. The stratospheric ozone layer protects us from __________.
A. Infrared radiation from the sun
B. Ultraviolet radiation from the sun
C. Cosmic radiation
D. X-rays from the sun
Correct Answer: B. Ultraviolet radiation from the sun
Expert Rationale: The ozone layer absorbs 97–99% of the sun's medium-frequency ultraviolet (UV-B)
radiation. Without this protection, increased UV radiation would reach Earth's surface, causing harm
to humans, animals, and plants.
5. Which health effect increases from loss of the stratospheric ozone layer?
A. Cases of cataracts or skin cancer
B. Respiratory infections
C. Heart disease
D. Diabetes
Correct Answer: A. Cases of cataracts or skin cancer
Expert Rationale: Increased UV-B radiation reaching Earth's surface due to ozone depletion leads to
higher rates of skin cancer (melanoma and non-melanoma), cataracts, and immune system
suppression in humans. It also damages crops and marine ecosystems.
6. What proves that HCFCs are in the stratosphere?
A. HCFCs found in air samples from the stratosphere
B. HCFCs found in ocean water
C. HCFCs found in soil samples
D. HCFCs found in rain water
Correct Answer: A. HCFCs found in air samples from the stratosphere
Expert Rationale: Direct evidence of HCFCs in the stratosphere comes from air samples collected by
high-altitude balloons and aircraft. These samples confirm that HCFCs do reach the stratosphere,
where they can release chlorine and deplete ozone, though to a lesser extent than CFCs.
, 7. What makes HFC refrigerants damaging to the environment?
A. They can have very high global warming potentials
B. They deplete the ozone layer
C. They are toxic to humans
D. They are flammable
Correct Answer: A. They can have very high global warming potentials
Expert Rationale: HFCs do not deplete stratospheric ozone (ODP = 0), but they are potent
greenhouse gases. Many HFCs have global warming potentials (GWPs) hundreds to thousands of
times greater than CO₂. For example, R-404A has a GWP of 3,922, and R-410A has a GWP of 2,088.
This is why the EPA and international agreements (like the Kigali Amendment) are phasing down
HFCs.
8. __________ makes HFO refrigerants less flammable than HC refrigerants.
A. Chlorine
B. Fluorine
C. Bromine
D. Iodine
Correct Answer: B. Fluorine
Expert Rationale: HFO (hydrofluoroolefin) refrigerants contain fluorine, which inhibits combustion.
HC (hydrocarbon) refrigerants like propane (R-290) and isobutane (R-600a) contain only hydrogen
and carbon, making them highly flammable. The presence of fluorine in HFOs significantly reduces
their flammability, though some HFOs are still mildly flammable (A2L classification).
9. Which refrigerant contains chlorine?
A. R-12
B. R-134a
C. R-410A
D. R-404A
Correct Answer: A. R-12
Expert Rationale: R-12 (dichlorodifluoromethane) is a CFC that contains chlorine. R-134a is an HFC
(no chlorine). R-410A is a blend of HFCs (R-32 and R-125, no chlorine). R-404A is a blend of HFCs (R-
125, R-143a, R-134a, no chlorine). Only CFCs and HCFCs contain chlorine.
10. HFO refrigerants are miscible in __________ lubricants.
A. Mineral oil
B. POE lubricants
C. PAG lubricants
D. Alkylbenzene lubricants
Questions and Correct (Verified) Answers | Latest Update
2026/2027 | Already Graded A+ | Guaranteed Success |
Brand New Version
1. Ozone depletion is caused by __________ in HFC refrigerants.
A. Chlorine
B. Fluorine
C. Bromine
D. Hydrogen
Correct Answer: B. Fluorine
Expert Rationale: HFC refrigerants do not contain chlorine, so they do not directly deplete
stratospheric ozone. However, the question as written in the original document appears to contain a
typo — it states "chlorine" as the correct answer, but HFCs (hydrofluorocarbons) contain no chlorine.
The ozone-depleting potential (ODP) of HFCs is zero. CFCs and HCFCs contain chlorine and are the
actual ozone-depleting substances. This question likely intended to ask about CFCs/HCFCs. For exam
purposes, remember: HFCs = no chlorine = no ozone depletion. If the question truly asks about
HFCs, the correct answer is that they do not cause ozone depletion through chlorine. The original
answer key appears erroneous.
2. CFCs and HCFCs __________ making them capable of reaching the stratospheric ozone layer.
A. Dissolve easily in water
B. Do not dissolve in water or easily break down in the atmosphere
C. Are heavier than air
D. React quickly with other chemicals
Correct Answer: B. Do not dissolve in water or easily break down in the atmosphere
Expert Rationale: CFCs and HCFCs are highly stable compounds. Because they do not dissolve in
water (rain cannot wash them out) and do not break down easily in the lower atmosphere, they
persist long enough to migrate to the stratosphere. Once there, UV radiation breaks them apart,
releasing chlorine atoms that destroy ozone.
3. According to the Rowland-Molina theory, __________ are destroyed by each chlorine atom in
the stratosphere.
A. 1,000 ozone molecules
B. 10,000 ozone molecules
,C. 100,000 ozone molecules
D. 1,000,000 ozone molecules
Correct Answer: C. 100,000 ozone molecules
Expert Rationale: The Rowland-Molina hypothesis (1974) proposed that chlorine atoms catalytically
destroy ozone. Each chlorine atom can destroy up to 100,000 ozone molecules before being removed
from the stratosphere. This catalytic cycle is why even small amounts of CFCs can cause significant
ozone depletion.
4. The stratospheric ozone layer protects us from __________.
A. Infrared radiation from the sun
B. Ultraviolet radiation from the sun
C. Cosmic radiation
D. X-rays from the sun
Correct Answer: B. Ultraviolet radiation from the sun
Expert Rationale: The ozone layer absorbs 97–99% of the sun's medium-frequency ultraviolet (UV-B)
radiation. Without this protection, increased UV radiation would reach Earth's surface, causing harm
to humans, animals, and plants.
5. Which health effect increases from loss of the stratospheric ozone layer?
A. Cases of cataracts or skin cancer
B. Respiratory infections
C. Heart disease
D. Diabetes
Correct Answer: A. Cases of cataracts or skin cancer
Expert Rationale: Increased UV-B radiation reaching Earth's surface due to ozone depletion leads to
higher rates of skin cancer (melanoma and non-melanoma), cataracts, and immune system
suppression in humans. It also damages crops and marine ecosystems.
6. What proves that HCFCs are in the stratosphere?
A. HCFCs found in air samples from the stratosphere
B. HCFCs found in ocean water
C. HCFCs found in soil samples
D. HCFCs found in rain water
Correct Answer: A. HCFCs found in air samples from the stratosphere
Expert Rationale: Direct evidence of HCFCs in the stratosphere comes from air samples collected by
high-altitude balloons and aircraft. These samples confirm that HCFCs do reach the stratosphere,
where they can release chlorine and deplete ozone, though to a lesser extent than CFCs.
, 7. What makes HFC refrigerants damaging to the environment?
A. They can have very high global warming potentials
B. They deplete the ozone layer
C. They are toxic to humans
D. They are flammable
Correct Answer: A. They can have very high global warming potentials
Expert Rationale: HFCs do not deplete stratospheric ozone (ODP = 0), but they are potent
greenhouse gases. Many HFCs have global warming potentials (GWPs) hundreds to thousands of
times greater than CO₂. For example, R-404A has a GWP of 3,922, and R-410A has a GWP of 2,088.
This is why the EPA and international agreements (like the Kigali Amendment) are phasing down
HFCs.
8. __________ makes HFO refrigerants less flammable than HC refrigerants.
A. Chlorine
B. Fluorine
C. Bromine
D. Iodine
Correct Answer: B. Fluorine
Expert Rationale: HFO (hydrofluoroolefin) refrigerants contain fluorine, which inhibits combustion.
HC (hydrocarbon) refrigerants like propane (R-290) and isobutane (R-600a) contain only hydrogen
and carbon, making them highly flammable. The presence of fluorine in HFOs significantly reduces
their flammability, though some HFOs are still mildly flammable (A2L classification).
9. Which refrigerant contains chlorine?
A. R-12
B. R-134a
C. R-410A
D. R-404A
Correct Answer: A. R-12
Expert Rationale: R-12 (dichlorodifluoromethane) is a CFC that contains chlorine. R-134a is an HFC
(no chlorine). R-410A is a blend of HFCs (R-32 and R-125, no chlorine). R-404A is a blend of HFCs (R-
125, R-143a, R-134a, no chlorine). Only CFCs and HCFCs contain chlorine.
10. HFO refrigerants are miscible in __________ lubricants.
A. Mineral oil
B. POE lubricants
C. PAG lubricants
D. Alkylbenzene lubricants
