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 (CF2Cl2). These air conditioners are recharged from stockpiled supplies of CFC-12. If each of the 100 million automobiles contains 1.2 kg of CFC-12 and leaks 20 % of its CFC-12 into the atmosphere per year, how much chlorine, in kg, is added to the atmosphere each year due to auto air conditioners? (Assume two significant figures in your calculations.)

In order to get the the amount of CFC-12 that is released into the atmosphere each year, we need to take the numbers that we have at disposal, which are 100 million automobiles that use it, 1.2 kg of CFC-12 in each of those automobiles, and leaks that account for 20% of the total weight of the used CFC-12.

First we need to see how much CFC-12 do all of the automobiles have, and we can do that with simply multiplying the number of automobiles by the amount they use:

100,000,000 x 1.2 = 120,000,000

So it turns out that all automobiles combined use 120 million kg of CFC-12. Now we need to find out the percentage of leaking that ends up into the atmosphere. In order to do this we need to divide 120 million with the number of total percentage, 100, and than multiply by 20 as that it is the percentage that ends up into the atmosphere:

120,000,000 / 100 = 1,200,000

1,200,000 x 20 = 24,000,000

We come to a result of 24 million, thus 24 million kg of CFC-12 is released into the atmosphere each year by the auto air conditioners.