You have a stock 0.100 M solution of KMnO4 and a series of 100-mL volumetric flasks. What volumes of the stock solution will you have to pipet into the flasks to prepare standards of 1.00, 2.00, 5.00, and 10.0x10^-3M KMnO4 solutions?

Question

I tried using M1V1=M2V2 but the answers didn't make sense

Answer 1

I see what you are saying, but lets start with the first dilution.

You want to prepare a 1 x 10^-3 M solution using 100mL volumetric flasks.

1 x 10^-3 M*(0.1L)= moles of KMnO4 required=1 x 10^-4 moles of KMnO4

1 x 10^-4 moles of KMnO4/stock solution= volume required= 1 mL of stock.

Pipette 1mL of stock into volumetric flask and add solvent until the bottom of the meniscus touches the 100 mL mark.

repeat this setup for the 2.00, 5.00, and 10 x 10 6-3 M solutions.

Answer 2

Oh wow. I just misread the standards the question was asking for. I was trying to make a 1.00M solution rather than a 1x10^-3M. I hope this is what my professor means with the way the question was written.

Answer 3

Let me point out that the dilution formula DOES work.
m1v1 = m2v2
0.1*v = 0.001*100
v = 0.001*100/0.1 = 01/0.1 = 1 mL.:-).

Answer 4

Yes, I used it for my calculations. Thank you.

Answer 5

It happens to all of us.

Good luck!!!!!!!!!!!!!!

Answer 6

In the last line of my response I omitted the decimal point.
It should read as follows:
v = 0.001*100/0.1 = 0.1/0.1 = 1 mL.:-(.