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University of Toronto

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Problem 113

Seawater is approximately 4.0$\%$ by mass dissolved ions, 85$\%$ of which are from NaCl. (a) Find the mass $\%$ of $\mathrm{NaCl}$ in seawater. (b) Find the mass $\%$ of Na' ions and of $\mathrm{Cl}^{-}$ ions in seawater.

Answer

mass percent of $\mathrm{NaCl}=0.034$ or 3,4 percent

mass percent of $\mathrm{Na}^{+}$ in the seawater $=0,0134$ or 1,34 percent

mass percent of $\mathrm{Cl}^{-}$ in the seawater $=0,0206$ or 2,06 percent

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## Discussion

## Video Transcript

So we're keeping the seawater 4% by mass, off civil jury signs. And also, we think those I 85% refusal in Korea. So first of all, what we would like to find out what would be. The master has a percentage off something Karajan overall, seawater. And also what will be the master? 10% of the individual. So the mine and Cora and in seawater. Okay, so ah, you know, that was a software 1st 1 we know that. Ah, the overall mass, um, 4% off that we behind. And we think that 4% 85% off. That will be something, Cory. So that one must be the standish off. So then, Cory, we have our 4% off to do. Ryan. We'll apply. Were for 85% off the ceiling, Cory. And then we we have the overall percentage. So we have soup on civil four times. New Appointee five. Or you can say that it's 4% times 85% and then we should be able to find it. It's peform poor 4% by mass. Off the sea water will be corresponding to ah, sodium call ry sudden Korea. Okay, So the Lexx, what would be the massive percentage off, Um, sodium and co writing water. So from RPV support, we can find that the over or feet 0.4% we contributed by Salim Cory. Okay, so when we actually less so in core, I counting one sodium When one call Write that in the formula. So from here we have found the master stand teach off sodium Angkor right in, maybe one in the formula. Okay, so let's file the tow tow mater mass total more than mess with every half hours. Um, sodium Tess. Ah, come core I So roughly around for the aid, you would be other different Depends on walk on the Massachusetts, but you move off the around 58. Ah, Grandpa Mo. Okay, so for the limbo moose off. Ah, I mean for the modem ass off. So the em field of masters percentage. From this morning from from this formula, we can see our Ah, well, the mass off our, um so the, um divide by the overall weight. So we will be 58 then we go to multiply that by 12% Onda we should be able to find out is what flee around? Um, some Ferdie. Ah, really finding a stew in points the United States owes for soup of ah, 3 47 4 Oh, uh, um s injuries. 40%. All right, So if we have 4% sodium, then there we meaning core. We must be close to one myself. 14 Where it's a wonder. Percent minus 60% at one. It's 40% of you agree 60%. So 60%. Okay, so we know that if you have something to arrive, 40% will be, ah, sodium. 60%. We recall. Right. Okay, so we have the dismiss Standish over here. We just need to multiply by this percentage Wi Fi. We can find a massive sodium and call right all throw you in seawater. Okay, so for sodium, we were half hour 40%. So super for time. Our fee for 4% and you should be equals 21.4%. And for cool right again. Will you take 60% times our fief? 14%. And then we We should have to point C before all 2.0%

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