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Q: Hydrogen in Earth's Oceans ( Answered ,   1 Comment )
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 Subject: Hydrogen in Earth's Oceans Category: Science Asked by: pdy-ga List Price: \$10.00 Posted: 17 Apr 2006 01:10 PDT Expires: 17 May 2006 01:10 PDT Question ID: 719696
 `Plus or minus %10 how many tons of Hydrogen are in the Earth's Oceans?`
 ```pdy-ga, The best scientific estimates put the mass of the world's oceans at about 1.37 x 10^21 kg: http://hypertextbook.com/facts/1998/AvijeetDut.shtml Mass of the Oceans The average salinity of the oceans is 35 parts per thousand: http://www.palomar.edu/oceanography/salty_ocean.htm ...Throughout the world, the salinity of sea water averages about 35 o/oo or 3 1/2% salt. Therefore, the oceans are 96.5% water, and amount of water in the oceans is: 96.5% of 1.37 x 10^21 kg = 1.32 x 10^21 kg. Each molecule of water is (by weight, and on average) 16 parts oxygen and 2 parts hydrogen, so that water is: 2/16 = 1/8th = 12.5% hydrogen. 12.5% of 1.32 x 10^21 kg = 0.165 x 10^21 kg = 1.65 x 10^20 kg. Therefore, there are 1.65 x 10^20 kg of hydrogen in the world's oceans, which can also be expressed as 1.65 x 10^17 metric tons. I trust that's what you needed. However, if there's anything else I can do for you, just let me know by posting a Request for Clarification. And thanks for a fun question! pafalafa-ga search strategy -- Google searches on: volume oceans average salinity oceans``` Clarification of Answer by pafalafa-ga on 17 Apr 2006 07:37 PDT ```Thanks to palitoy-ga for politely pointing out an error in my calculations, which -- though small -- is certainly not an insiginificant one. The corrected calculations are: ========== Each molecule of water is (by weight, and on average) 16 parts oxygen and 2 parts hydrogen, so that water is: 2/18 = 1/9th = 11.1% hydrogen. 11.1% of 1.32 x 10^21 kg = 0.147 x 10^21 kg = 1.47 x 10^20 kg. Therefore, there are 1.47 x 10^20 kg of hydrogen in the world's oceans, which can also be expressed as 1.47 x 10^17 metric tons. ========== Again....let me know if there's anything else you need on this. paf```
 ```Just a minor correction to pafalafa-ga's reasoning which is obviously a typo on his part - water is approximately 16 parts oxygen and approximately 2 parts hydrogen by atomic mass. Hydrogen atoms therefore make up 2/18 of the mass and not 2/16 as stated.```