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Fundamentals G21

Posted: Tue Apr 10, 2018 9:18 pm
by paulacamara1E
When going over problem G21 I was quite confused why after finding the number of moles for K2S we have to multiply by 2molK+/1molK2S? I figured it might be because there are two K but I don't really understand why multiply. Can someone explain?

Re: Fundamentals G21

Posted: Tue Apr 10, 2018 10:14 pm
by jadam_1E
Because the objective of this question is to find the concentration of potassium ions, we need to find how many moles of potassium are in the solution. For every mole of K2S there will be 2 moles of K, so you can multiply the number of moles K2S by 2 to find the number of moles of K in the solution because of K2S. Similarly, we multiple the number of moles of K3PO4 by 3 to find the amount of K in the solution because of K3PO4 and we multiply the number of moles of KCl by 1 to find the amount of K in the solution because of KCl.

The concentration of potassium will be the sum of these individual contributions of K/.500L