Question

A person aboard a ship in the middle of the Atlantic Ocean reaches down and collects exactly one liter of sea water. He then returns the water back to the sea. Suppose that enough time passes that the water he collected becomes equally dispersed throughout all the oceans in the world. At some other location on one of the oceans a person reaches down and collects exactly one liter of seawater. How many molecules of water (H2O) from the first liter collected will likely be present in the second liter? Any suggestions? I've been given: radius of the earth is 6371 km, surface are of a spherre is 4

Answer 1

surface are of a sphere is 4[pi]r^2, 71% of the surface of the earth is covered by oceans with an average depth of 3790 meters, nand one mole of water contains 6.02*10^23.

Answer 2

What you need to do is figure out the number of H2O molecules in the bucket and estimate the number of H2O molecules in the ocean.

Then calculate the ratio of the two, the is the expected proportion of water from the first bucket in the second bucket, and then multiply that number again by the number of molecules in the bucket to get the actually expected number of molecules

Answer 3

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This sort of thought experiment is entertaining and alarming. It is highly likely, for instance, that right now I have molecules of O2 in my lungs that Mozart breathed, or Einstein.

But is just about equally likely that I also have O2 molecules from Hitler.

Answer 4

i can find the area of the ocean but it would be in meters^3. How would I estimate the total amount of molecules in the ocean.

Answer 5

You know that one cubic cm of water is 1 gram of water. From that and the molecular weight of H2O, you can deduce the number of atoms in 1 gram of water. Then you can convert cubic m into # molecules

Answer 6

correction: " ... you can deduce the number of MOLECULES in 1 gram of water."

Answer 7

make sense?

Answer 8

im working it now to see if it makes sense. Having trouble finding the amount of wter in the ocean. It area of the earth, convert to m^2, times by 71%, and then times by 3790 M to give you m^3?

Answer 9

Take 4.pi.R_earth^2 (m^2) times 71% times 3790 m

Answer 10

but whn you take the area of the ocean it gives it to you in km, not meters. so wouldnt there be a conversion?

Answer 11

yes, of course.

Answer 12

Alright, I think I understand. But just to be sure, will you work this problem and post your answer? Then when I get back on later, I can compare my answer to yours. This would be a great help if you would.

Answer 13

Alright i've figured out the molecules of H2O in the first bucket and in the ocean. But how do I figure out the number of molecules in the second bucket compared to the first.

Answer 14

Assume they're the same size.

Answer 15

i mean how do i figure out the number of molecules from the first bucket in the second bucket. You mentioned the ratio above but i dont understand completely.

Answer 16

Alright I got 3.34*10^25 molecules of water in the first bucket and 4.590358653*10^39 molecules of water in the ocean. Now it is mentioned above that I need to take the ratio of the two and that would equal the number of molecules from the first in the second bucket. Does that mean I need to divide 4.590358653*10^39 by 3.34*10^25? Then it is mentioned to multiply that number by the number of molecules in the first bucket, but wouldnt this just get me back to the number of molecules in the ocean?

Answer 17

Well the amount of Oxy. in H20 is )o2.So if you x that to the amout of sea water you could get your anwser or a possible estimate :D Hope that helped