[RubberDucky]

I have a prelab question that wants me to identify initial concentrations of substances [A] and [ B].
I'm trying to determine reaction rates but I've only ever done it with concentration given. I know m1v1=m2v2 for dilution, but I don't know if that applies here. I initially was using .008M*.01L=M2*.04L but then I thought about it and asked myself if I needed to factor in 10, 10, and 30ml of solution [ B] into total volume (when I want concentration of solution [A]). In short I don't know what volume to use or even if this formula is applicable with 2 solutions.  Ultimately I have 2A+3B=>C+2D and Rate_a=1/2([A concentration]/[t consumption]) but I wasn't given a rate, and I am unsure of concentration. The lab manual holds my hand, but skips this part and I think I could be over-analyzing. We are working on reaction rates and reaction orders this week.

The information I have is that
Experiment #
1 - [A] is .008M and 10ml are used, [ B] is .2M and 10ml are used, finally 30ml of distilled water are used. A disappears after 82 seconds
2- [A] 20ml; [ B] 10ml; [distilled] 20ml; 41 seconds
3-[A] 10ml; [ B] 30ml; [distilled] 10ml; 41 seconds


Thanks in advance.

[Borek]

It is about simple dilutions, and yes, m₁v₁=m₂v₂ is all that is needed.

http://www.chembuddy.com/?left=concentration&right=dilution-mixing

[RubberDucky]

How do I account for the distilled water? Won't the concentration of it be 0? What is my final volume, do I use 50ml? help please. The lab manual is ambiguous. It provided the table that I typed in and asked for initial concentrations of A and B. It said calculate them. To me, the concentrations are given.

[AWK]

Won't the concentration of it be 0?[/quote
Can distilled water contain your substances A or B?