To determine how much of an 18% (m/m) KI solution is needed to contain 2.50 grams of KI, we can follow these steps:
1. Understand what 18% (m/m) means: In a solution, 18% (m/m) indicates that there are 18 grams of potassium iodide (KI) per 100 grams of solution. This means the mass percentage of KI in the solution is 18%.
2. Set up the proportion: We need to find the total mass of the solution that contains 2.50 grams of KI. We can use the equation which relates the mass of the solute (KI) to the mass of the solution using the percentage concentration:
[tex]\[
\text{mass\_solution} = \frac{\text{mass\_solute}}{\text{percentage\_concentration}}
\][/tex]
Here, the mass of the solute (KI) is 2.50 grams, and the percentage concentration is 18% or 0.18.
3. Solve for the mass of the solution:
[tex]\[
\text{mass\_solution} = \frac{2.50 \, \text{g}}{0.18}
\][/tex]
4. Calculate the mass required:
[tex]\[
\text{mass\_solution} = 13.88888888888889 \, \text{g}
\][/tex]
Therefore, you would need approximately 13.89 grams of an 18% (m/m) KI solution to contain 2.50 grams of KI.
