Question

You have 363 mL of a 1.25M potassium chloride solution, but you need to make a 0.50M potassium chloride solution. How many millimeters of water must you add to the original 1.25M solution to make the 0.50M potassium chloride solution? NOTE: Assume the volumes are additive.

______mL of water need to be added

Answer 1

To make a 0.50M potassium chloride solution from a 1.25M solution, you need to dilute it by adding water. The volume of water needed is 89.50 mL.

Step-by-step explanation:

To make a 0.50M potassium chloride solution from a 1.25M solution, you need to dilute it by adding water.

The volumes of the original solution and the water are additive, so you can calculate the volume of water needed to achieve the desired concentration.

The formula for dilution is:

C1V1 = C2V2

Where C1 is the initial concentration, V1 is the initial volume, C2 is the final concentration, and V2 is the final volume.

In this case, C1 = 1.25M, V1 = 363 mL, C2 = 0.50M, and V2 = V1 + the volume of water needed.

Plug in the values:

(1.25M)(363 mL) = (0.50M)(363 mL + Vw)

Solve for Vw, the volume of water needed:

452.50 mL - 363 mL = Vw

Vw = 89.50 mL

Therefore, you need to add 89.50 mL of water to the original 1.25M solution to make a 0.50M potassium chloride solution.

Answer 2

Answer:- 544.5 mL of water need to be added.

Solution:- It is a dilution problem. The equation used for solving this type of problems is:

`M_1V_1=M_2V_2`

where,
`M_1` is initial molarity and
`M_2` is the molarity after dilution. Similarly,
`V_1` is the volume before dilution and
`V_2` is the volume after dilution.

Let's plug in the values in the equation:

`1.25M(363mL)=0.50M(V_2)`

`V_2=(1.25M(363mL))/(0.50M)`

`V_2=907.5mL`

Volume of water added = 907.5mL - 363mL = 544.5 mL

So, 544.5 mL of water are need to be added to the original solution for dilution.