Chlorofluorocarbon Properties & Environmental Impact Flashcards
7 cards from real CFC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Chlorofluorocarbon Properties & Environmental Impact flashcards as text
What UV radiation wavelength range (nm) is most effectively absorbed by stratospheric ozone, protecting life on Earth?
Answer: UV-B: 280–315 nm
Stratospheric ozone primarily absorbs UV-B radiation (280–315 nm), which is the range most damaging to DNA, skin cells, and marine ecosystems.
The Halogen numbering system for refrigerants: what does the digit in the 'tens' place of a three-digit refrigerant number indicate?
Answer: Number of carbon atoms minus one
In the ASHRAE refrigerant numbering system, the tens digit equals the number of carbon atoms minus one; for single-carbon molecules (methane-based), this digit is 0.
Which greenhouse gas metric compares the warming impact of a CFC relative to CO₂ over a 100-year period?
Answer: Global Warming Potential (GWP)
Global Warming Potential (GWP) quantifies how much heat a greenhouse gas traps over 100 years relative to CO₂, which is assigned a GWP of 1.
R-114 (CFC-114) was commonly used in which specific application before its phase-out?
Answer: Centrifugal chillers for large building cooling
R-114 (dichlorotetrafluoroethane) was used in centrifugal chillers for large commercial and industrial cooling applications due to its low pressure operating characteristics.
What is the primary reason CFC molecules are so stable in the lower atmosphere (troposphere)?
Answer: They lack C-H bonds and are resistant to hydroxyl radical attack
CFCs lack hydrogen atoms, so the hydroxyl (OH) radical—which breaks down most organic compounds in the troposphere—cannot attack them, allowing CFCs to persist and migrate to the stratosphere.
According to EPA regulations, what is the maximum allowable leak rate for commercial refrigeration equipment with a charge over 50 lbs before repair is required?
Answer: 20% per year
Under EPA Section 608 regulations, commercial refrigeration equipment with charges over 50 lbs must be repaired if the annual leak rate exceeds 20% of the system charge.
Which physical property causes CFCs to migrate upward from the troposphere to the stratosphere despite being denser than air?
Answer: Atmospheric mixing and diffusion over decades
Although CFCs are denser than air, they are transported to the stratosphere through atmospheric mixing, turbulence, and slow diffusion over many years rather than density-driven settling.