[kverge]

I'm stuck again.

Solution A .010M KIO3 is mixed with Solution B NaHSO3. First reaction: Volume of KIO3 10mL, Volume of Water 0mL, Concentration of KIO3 .01M Second Reaction: Volume of KIO3 9mL, Volume of Water 1mL

I am supposed to find the concentration of KIO3 in the Second reaction.

I know the formula is M1V1 = M2V2. I am confused because Water is added and KIO3 is removed so the overall volume doesn't change. Do I use the overall volume of 10ml. Or do I use the volume of KIO3 of 9ml

the first half of the formula I think would be (.01M)(10mL) but if I use the overall volume which doesn't change the volume on the other side is also (10mL) which doesn't change the concentration.

I can not find any example questions that don't have the volume change. All of them just add water to dilute. None of them remove the same amount of solute as the water they added.

I don't understand this at all!

[Borek]

You take 9 mL of KIO₃ and you add 1 mL of water, this is just dilution.

[kverge]

Oh! Duh. That makes sense. I can't believe I didn't think of that. I just calculate the number of moles in the 9ml of KIO3 using the molar mass then? Thank you!

[Borek]

No need for molar mass. You were given molar concentration.