Question

Calculate the number of moles and the mass of the solute in each of the following solutions:

(a) 325 mL of 8.23 × 10⁻⁵ M KI, a source of iodine in the diet

Answer 1

To determine the number of moles of KI in a 325 mL 8.23 × 10⁻⁵ M solution, convert the volume to liters and use the formula (molarity × volume). For the mass of solute, multiply the moles by the molar mass of KI. The solution contains 2.67475 × 10⁻⁷ moles and 4.440785 × 10⁻⁵ g of KI.

Step-by-step explanation:

To calculate the number of moles of solute in a solution, we use the formula:

Number of moles = Molarity (M) × Volume (L)

For solution (a), 325 mL of 8.23 × 10⁻⁵ M KI:

First, convert the volume from mL to L:

325 mL × (1 L / 1000 mL) = 0.325 L

Now calculate the moles of KI:

8.23 × 10⁻⁵ mol/L × 0.325 L = 2.67475 × 10⁻⁷ moles of KI

To determine the mass of the solute, multiply the number of moles by the molar mass of KI (which is approximately 166 g/mol):

2.67475 × 10⁻⁷ moles × 166 g/mol = 4.440785 × 10⁻⁵ g of KI