Question

100.0 mL of a 0.695 M solution of KBr is diluted to 500.0 mL. What is the new concentration of the solution?

Answer 1

After diluting 100.0 mL of a 0.695 M KBr solution to 500.0 mL, the new concentration of the KBr solution is 0.139 M.

Step-by-step explanation:

When diluting a solution, the amount of solute remains constant while the volume changes. This relationship can be represented by the formula M1V1 = M2V2, where M1 and V1 are the molarity and volume of the initial solution, and M2 and V2 are the molarity and volume of the diluted solution.

To solve for the new concentration after dilution, you can set up the equation using the provided initial conditions (M1 = 0.695 M, V1 = 100.0 mL) and the final volume (V2 = 500.0 mL) then solve for M2. Applying the equation: (0.695 M)(100.0 mL) = (M2)(500.0 mL), gives us M2 = (0.695 M)(100.0 mL) / (500.0 mL), which simplifies to M2 = 0.139 M. Therefore, the new concentration of the KBr solution after dilution to 500.0 mL is 0.139 M.

Answer 2

0.116 M

Step-by-step explanation:

(Step 1)

Calculate the amount of moles using the molarity ratio.

100.0 mL / 1,000 = 0.1000 L

Molarity = moles / volume

0.695 M = moles / 0.1000 L

0.0695 = moles

(Step 2)

Calculate the new molarity using the moles and new volume.

500.0 mL / 1,000 = 0.5000 L

Molarity = moles / volume

Molarity = 0.0695 moles / (0.1000 L + 0.5000 L)

Molarity = 0.0695 moles / (0.6000 L)

Molarity = 0.116 M