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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