[inspiration100]

Hey guys!  I just got off spring break and I have a new lab already!  We're starting a clock reaction lab.  They Idea is we need to come up with an equation for the reaction so we can spit out the time it will take for any concentration of either S₂O₈ or I^-.  I'm a little confused about a few things, so the easier explaining you can do the better since I'm pretty dense  .

First, my book has something strange in it when explaining how to use the rate law.  In order to determine the reaction orders, it converts the rate into mol/L x seconds.  Why do they do this?  Why not just list seconds?  Also, why is it called the Initial Rate instead of just Rate? (screenshot can be seen here http://img211.imageshack.us/img211/2626/img360yt3.jpg)

Secondly, when I perform the experiment, how can I change the concentration of the substances like they did in the above screenshot?  If I'm given a solution, the only thing I can do is dilute it, not make it more concentrated.  Right?  So do I dilute the first solution and then make the second less dilute, or can I perorm this the other way around?  Perform it and then dilute it?

LASTLY and most importantly.   This equation only works for concentration.  How can I make it work for volume?  The whole idea behind the lab is the fact that she gives us a volume and we calculate how it changes.  How can We make this work for volume?

I'll have more questions later tonight, but if you can help me with these, I'd be much appreciated!