[SRPang89]

http://www.ocean.washington.edu/courses/oc400/PS1_2011.pdf

#3. I am so lost!! Can ANYONE *delete me*? I would have just posted the question here but the table didn't turn our right.

ANY help would be GREATLY appreciated!
Thank you!

[DevaDevil]

a) assume all compounds will dissolve well and not precipitate, then make a small table:
Put the individual ions on the horizontal, and the compounds she has on the vertical index like:

             |  Na | Mg | Ca | K | Cl | SO₄ |
a NaCl     |
b MgSO₄  |
c CaCl₂    |
d HCl       |
e KOH      |
f Mg(OH)₂ |


where a - f represent the amount of moles each of the compounds needs to have in the final seawater solution
then fill the appropriate letter in the column (for example, put "a" in the column of Na next to NaCl, because a moles of NaCl will give a moles of Na)

then add for each of the elements vertically how much each of the compounds will contribute to the ions. For example: Mg-column will be b + f, because b moles of MgSO₄ and f moles of Mg(OH)₂ will contribute to give (b+f) moles of Mg²⁺

then do the algebra to solve how much each of the compounds needs to be: Example: Na-column will give "a", which means a=470 mmol, as seawater has 470 mmol Na⁺

then finally the whole mixture will be complemented with water to make 1 kg.

b) then you know the amount of moles of the ions, and you know their weight. Thus you also know the weight of the water (1kg minus the weight of the ions), with the density of that water given, you should be able to calculate the moles per liter