# chemistry

posted by
**manny** on
.

-2.60-

Hi here is a question I am having trouble with. I need help only on part c.

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Each time you inhale, you take in about 500 ml (two sigfigs) of air, each millileter of which contains 2.5 x 10^19 moleules. In delivering the Gettysburg Adress, Abraham Lincoln is estimated to have inhaled about 200 times.

a.) How many molecules did Lincoln take in?

My answer: 200 * (500 ml) * (2.5 x 10^19 molecules / 1 ml) =

2.5 x 10^24 molecules

b.) In the entire atmosphere, there are about 1.1 x 10^44 moleules. What fraction of the molecules in the Earth's atmosphere was inhaled by Lincoln at Gettysburg?

My Answer: (2.5 x 10^24)/(1.1 x 10^44)=

2.3 x 10^-20

c.) In the next breath that you take, how many molecules were inhaled by Lincoln at Gettysburg?

***I don't understand what this part of the question is asking for. How do I go about this?