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

Jul 18, 2016

$\text{5160 mg}$

#### Explanation:

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

As you know, a solution's percent concentration by mass, $\text{% m/m}$, 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 $\text{5.00% m/m}$ potassium iodide solution contains $\text{5.00 mg}$ of potassium iodide for every $\text{100 mg}$ 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 $\text{258 mg}$ 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.