Question

To what volume should you dilute 60.0 mL of a 4.50 M KI solution so that 30.0 mL of the diluted solution contains 3.25 g of KI?

Answer 1

Answer:

You should dilute to 414.1 mL

Explanation:

Let's apply the dilution formula to solve this:

M conc . Vol conc = M dil . Vol dil

Molarity for concentrated solution → 4.50 M

Volume for concentrated solution → 60 mL

Molarity for diluted solution → Unknown

Volume for diluted solution → Answer

Let's determine the molarity for diluted solution with data given.

We convert the mass of KI to moles

3.25 g . 1 mol/166 g = 0.0195 moles

Let's convert the volume from mL to L

30 mL . 1 L/1000mL = 0.030 L

Molarity (mol/L) = 0.0195 mol /0.030L = 0.652 M

We replace the data in the formula

4.50 M . 60 mL = 0.652 M . Volume for diluted solution

(4.50M . 60mL) / 0.652M = Volume for diluted solution

414.1 mL = Volume for diluted solution

Answer 2

Answer: 413mL

Explanation:

Molar Mass of KI = 39 + 127 = 166g/mol

Mass conc of KI = 3.25g

Number of mole = Mass conc/Molar Mass

Number of mole = 3.25/166 = 0.0196 mol

But recall

Molarity = number of mole / Volume

Number of mole = 0.0196 mol

Volume = 30mL = 30/1000 = 0.03L

Molarity = 0.0196/0.03

Molarity = 0.653M

C1 = 4.5M

V1 = 60mL = 60/1000 = 0.06L

C2 = 0.653M

V2 =?

C1V1 = C2V2

4.5 x 0.06 = 0.653 x V2

V2 = (4.5 x 0.06) / 0.653

V2 = 0.413L

Converting to mL

0.413 x 1000 = 413mL