[lilianag]

How do i go about doing this....
Suppose you are given exactly 1 liter of a 1.00 x 10^-3 M solution of toluene C6H5CH3 dissolvedin benzene C6H6. Exactly 1 ml of this solution is taken and diluted to exactly 1 liter with benzene. Call the resulting solution #2. Next take exactly 1 ml of solution #2 and dilute it to exactly 1 liter with benzene. Call the resulting solution #3. Continue in this manner until you get to solution #8. What is the concentration of solution #8? Calculate the number of molecules of toluene in 1 liter of solution #8. Interpret your result...

[discodermolide]

1 Liter = 1000 mL, you know the concentration per liter, therefore how much toluene (in moles) is present in 1 mL?
Keep going until you reach solution no 8.
You know the concentration in moles of solution 8 therefore you know the number of molecules.

Or you can start by working out how many molecules are in 1 mL of solution 1 and so on until you reach solution 8, therefore you know the concentration.
There is probably a mathematical formula for this but I don't know it!

[lilianag]

what is the concentration?

[discodermolide]

What do you mean by that? I don't quite understand.
The concentration is mass per volume.