chemistry
posted by Brittany .
If 100 mL of a 3 M solution of sodium hydroxide is diluted to a total volume of 600 mL with distilled water, what will the final concentration of sodium hydroxide be?

You can do it one of two ways.
1. Use the dilution formula.
mL x M = mL x M
2. Use reason. You know that it must be more dilute going from 100 mL to 600 mL. So the molarity is
3M x (100/600) = ??
3. A third way, and one some students like is to do it with moles.
How many moles do you have in the original solution? You have M x L = 3 M x 0.1L = 0.3 mole.
You must have 0.3 mole in the diluted solution, of course, but the final volume is 600 mL or 0.6 L.
M = moles/L = 0.3/0.6 = ?? 
0.5M