Question

A 60.0 mL portion of a 1.20 M solution is diluted to a total volume of 228 mL. A 114 mL portion of that solution is diluted by adding 135 mL of water. What is the final concentration? Assume the volumes are additive.

I kept doing this and got 0.289 but that was incorrect.

Answer 1

Answer:
`0.145M`

Step-by-step explanation:

Let's break down the problem step by step.

Step 1: Initial concentration and volume.

Initial volume = 60.0 mL

Initial concentration = 1.20 M

Step 2: Dilution of the initial solution.

The solution is diluted to a total volume of 228 mL.

To find the new concentration, you use the dilution formula:

`C1V1 = C2V2`
Where:
C1 = INITIAL CONCENTRATION
V1 = INITIAL VOLUME
C2 = FIND CONCENTRATION
V2 = FINAL VOLUME

Plugging in the values:

`1.20M×60.0mL=C2×228mL`

Solving for C2:


So, after the first dilution, the concentration is approximately

0.316M.

Step 3: Taking a portion of the diluted solution.
A 114 mL portion of the solution is taken

Step 4: Diluting further by adding 135 mL of water.
- Total volume after dilution = 114mL + 135mL = 249mL
Using the dilution formula again:

`C1V1=C2V2`
0.316M x 114mL = C2 x 249mL

Solving for
`C2`

`C2=(0.316M*114mL)/(249mL) =0.145M`
The final concentration is approximately 0.145M.

So, the final concentration is approximately 0.145M, not 0.289 as you initially calculated. It seems you may have made a calculation error in one of the steps.