Stoichiometry : dilution questions I need 500 ml of 0.2 mol/L  H2SO4 for a tutration lab. What volume in mL  of the 18 mol/L stock solution should you use?

I think this is a dilution question asking me to use C1V1=C2V2. I am confused because it sounds like s dilution question, but its asking for volume so i could possibly be using the (v/v) formula. If someone could help me out that would be greatly apprecaiated, trying to study for a test.
I gotchu.

It's definitely a dilution question. Just plug it into the equation you have, C1V1=C2V2.

$C_1V_1=C_2V_2$

$(0.2\: M)(500\: mL)=(18\: M)(x\: mL)$

Solve for x:

$x=5.56\: mL$

Therefore, you want to use 5.56 mL of 18 M stock solution. To make your 500 mL of 0.2 M sulfuric acid, just take the 5.56 mL of the stock solution, then fill it up with water until you have 500 mL total solution.

The idea behind the equation, by the way, is to preserve the number of moles in the solution while changing the total volume of the solution. Here, we find out that (0.2 M)(0.5 L) = 0.1 mol of sulfuric acid is needed in the final solution. So, we find the amount of stock solution needed to provide that 0.1 mol of sulfuric acid, by dividing 0.1 mol by the concentration of the stock solution.