Question 1196958
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A 900-gram salt-and-water solution contains 80 g of salt. 
This mixture is left in the open air, and 100 g of water evaporates 
from the solution. What is the percent concentration of salt in the remaining solution?
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<pre>
    +------------------------------------+
    |   Water evaporates, the salt not.  |
    +------------------------------------+


After evaporation 100 g of water, the mass of the mixture is 900 - 100 = 800 grams.


Of this mass, 80 grams is salt: it remains with no change.


So, the mass concentration of the remaining mixture is  


    {{{80/800}}} = {{{1/10}}} = 0.1 grams of salt per gram of the resulting mixture.    <U>ANSWER</U>
</pre>

Solved.


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<H3>The major lesson to learn from my solution is THIS :</H3>

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   &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Water evaporates, &nbsp;the salt not.  


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