Question

A container has 800.0 mL of an aqueous solution containing K+ ions. How many grams of K+ ions are in the solution if the molarity is 0.649 M?

Answer 1

Answer: There are 20.24 grams of $K^+ ions$ in the solution if the molarity is 0.649 M.

Explanation:

Molarity equals number of moles in a liter of solution as follows.

                  $M = \frac{no. of moles}{volume in liters}$

and, $Number of moles equals = \frac{mass}{molar mass}$

Therefore, $Molarity = \frac{mass}{molecular weight \times volume}$

Now, putting values in the above formula as follows.

      $Molarity = \frac{mass}{molecular weight \times volume}$

     $0.649 = \frac{x \times 1000}{39 \times 800}$    

(convert the volume from milliliter to liter)

       $x = 20.24 grams$

Thus, there are 20.24 grams of $K^+ ions$ in the solution if the molarity is 0.649 M.