Chemistry Dilution Problem

Say if you had 5 ml of 0.005M you can take 4 ml of this solution and add 1 ml of water to it to get 5ml of 0.004M. Make sense?

Ah, I see, I see...lol that sounds simple

So then to make 0.003 from 0.004 you just take 3 ml of this solution and add 1 ml of water to it? And then you keep doing that? I feel I'm missing something major here...

Does m1v1 = m2v2 come into this? So say if I had 25cm3 of 0.004M then to get 0.003M I would need 33.3 cm3 of water?

I made the volumes simple



Nope, that's not right.



I don't ever recall using that equation...you mean concentration = moles/volume?

All you have to do is keep perspective on the number of moles you have

So 25cm3 of 0.004 M = 0.0001 moles

concentration you want = 0.003 M so the volume you need is indeed 33.3 cm³

Ahh I see...

One last thing (sorry for the questions lol), but 33.3 cm3 is the volume of 0.003M solution I need. What I'm wondering is how much water I need to add to the 25cm3 of 0.004M solution to obtain 0.003M...so would that just be 33.3-25 = 8.3cm3 of water?

Thanks so far by the way, youve been a great help

EDIT: I might be overcomplicating things...

Yep, just the simple subtraction will get you the amount of water you need to add