Reef Chemistry Question of the Day #117 Sodium and Chloride in Seawater

[Randy Holmes-Farley]

Reef Chemistry Question of the Day #117

Typical ocean water has a salinity of 35 ppt. What portion of that 35 ppt is provided by sodium and chloride?


A. 30.2 ppt
B. 26.1 ppt
C. 22.4 ppt
D. 18.2 ppt

Good luck!







































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[Randy Holmes-Farley]

Don't be shy!

 

[reefjunkie53]

None of the above lol

 

[reefjunkie53]

I would have to say A

 

[reefjunkie53]

Don't they represent more than 85% of dissolved solids in natural sea water

 

[glb]

I would say A too because I know salt is by far the biggest ingredient in sea water.

 

[redfishbluefish]

I'm too lazy to look it up, but if what Reefjunkie says above about 85 percent is sodium chloride, the closest one would be A, about 30.2

 

[james2662]

I would think A as well since most salts contain chloride even if not all are sodium chloride.

 

[beaslbob]

I have no idea but assume almost all is sodium chloride.
So a

 

[zemuss]

A seems to be right after further research.. lol

 

[beaslbob]

A seems to be right after further research.. lol

naaaaa that can't be right. My guesses are always wrong.

 

[zemuss]

Did this ever get an answer?

 

[redfishbluefish]

Well, I went and looked it up!

According to the above reference, 85.6 percent is sodium chloride, so:


35ppt X 0.856 = 30ppt


The closest answer is "A", 30.2ppt


EDIT TO ADD: Something just hit me.....some of that chloride could be associated with the other salts......and actually some of the sodium too!!! So let me rethink this....need a periodic table.... Upon further reflection, sticking with "A." For the next lowest to be considered, the percent sodium chloride would be around 75 percent, and there is not enought of the other salts to share in the sodium and chlorine in the chart above. Hope this jibberish nonsense makes some sense.

2ND EDIT: Just reread the query......Randy is just asking for sodium and chloride....so disregard my nonsense in the first edit....IT'S A. That referenced chart above is all that is needed.

 

[Randy Holmes-Farley]

Did this ever get an answer?

I let them run a few days to give everyone a chance before giving the final answer.

 

[Randy Holmes-Farley]

And the answer is...A. 30.2 ppt

Sodium in 35 ppt seawater is 10,800 ppm, or 10.8 ppt.

Chloride in 35 ppt seawater is 19,400 ppm, or 19.4 ppt.

So the total of sodium and chloride is 10.8 ppt + 19.4 ppt = 30.2 ppt.

Happy Reefing.