What mass of solution containing 5.00% potassium iodide, KI, by mass contains 258 mg KI?

1 Answer
Stefan V.
Jul 18, 2016

"5160 mg"

Explanation:

Your goal here is to figure out the mass of your "5.00% m/m" potassium iodide solution that contains "258 mg" of potassium iodide, which is your solute.

As you know, a solution's percent concentration by mass, "% m/m", is calculated by taking the number of parts of solute you get per 100 parts of solution.

In this case, you can say that a "5.00% m/m" potassium iodide solution contains "5.00 mg" of potassium iodide for every "100 mg" of solution.

You can thus use the solution's percent concentration as a conversion factor to figure out how many milligrams of solution would contain "258 mg" of solute

258 color(red)(cancel(color(black)("mg KI"))) * "100 mg solution"/(5.00color(red)(cancel(color(black)("mg KI")))) = color(green)(|bar(ul(color(white)(a/a)color(black)("5160 mg solution")color(white)(a/a)|)))

The answer is rounded to three sig figs.

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