Because of increasing evidence of damage to the ozone layer, chlorofluorocarbon
ID: 772023 • Letter: B
Question
Because of increasing evidence of damage to the ozone layer, chlorofluorocarbon (CFC) production was banned in 1996. However, there are about 100 million auto air conditioners that still use CFC-12 (CF2CI2). These air conditioners that are recharged from stockpiled supplies of CFC-12. If each of the 100 million automobiles contains 1.1 kg of CFC-12 and leaks 25% of its CFC-12 into the atmosphere per year, how much CI in kilograms is added to the atmosphere each year due to auto air conditioners? (Assume two significant figures in your calculations.)Explanation / Answer
This is a dimensional analysis problem. The key to solving these types of problems is 2 things. 1) using dimensional analysis, 2) sorting through the problem and identifying the "fixed value" and the "conversion factors" so... fixed values... 100 million cars conversion factor(s)... 1.2kg freon / car 20kg freon leaked / 100kg freon 70.9kg Cl / 120.9kg freon do you understand all that? then.. we convert...start with the "value" on the left.. convert to the right... 100x10^6 cars x (1.2kg freon / car) x (20kg freon leaked / 100kg freon) x (70.9kg Cl / 120.9kg Freon) = 7.0x10^6 kg Cl