[ixi]

how do i find the final concentration of the solution?
Step 1) Solution A has a FW = 480.39
0.0192 g was used to make 100 mL

Step 2) 1 mL was taken from the 100 mL and diluted to 10 mL (so 1 mL solution, 9 mL di water)

Step 3) next, 1 mL was taken from the solution made in step 2, and that was diluted to 10 mL (so once again, 1 mL solution, 9 mL di water)

how do I figure out the final concentration?


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I know I have to use M1V1 = M2V2 somehow...

I figured out the M (from step 1) to be 4.0 * 10 ^ -4

now what do i do? help please

[macman104]

K, good, so the M of 1st step solution was 4 x 10^-4.

Do you know what M₁V₁ = M₂V₂ means (can you explain what each variable is)?

[ixi]

M1V1 = M2V2

M1 and V1 is the molarity and volume of solution 1
and M2, V2 is the molarity and volume of solution 2


I think for me, M1 is 4 x 10^-4 and V1 is 100 mL
so would that be (4 x 10^-4)(100) = (M2)(10 mL)

[macman104]

Careful, don't fall into the trap.  You made 100 mL of solution, but are you diluting all 100mL of it?

[ixi]

no, only 1 mL


would i use 1 mL instead for V1?
(4 x 10^-4)(1 mL) = (M2)(10 mL)
M2 = 4 * 10^ -5

[macman104]

Yup!  Good job!

[Borek]

Just don't forget it wasn't the last step.

[ixi]

then it's

(4 * 10 ^ -5) (1 mL) = (M2)(10 mL)
M2 = 4 * 10 ^ -6 M   right?