You wish to make a 0.337 M nitric acid solution from a stock solution of 3.00 M nitric acid. How much concentrated acid must you add to obtain a total volume of 75.0 mL of the dilute solution?

Answer 1

Actually, if you use the dilution formula C1V1 = C2V2, you don't have to convert to Liters, as long as both volume units are the same they will either cancel (if you know the volumes and are finding concentration) or you will just find your answer in those units. Iif you were actually trying to find moles of solute, you would have to convert to Liters, because Molarity is "moles of solute per liter of solution". Or you could say that it is "moles of solute per 1000 mL of solution" since 1 L = 1000 mL, these would be saying the same thing!

Regardless, when you plug in your numbers, the result would be 8.425 mL, not 0.8425 mL. However you have only 3 sig figs, which means your final answer should be 8.43 mL (assuming you were taught to round up if it is exactly halfway).

Answer 2

To solve this you need to use the formula for dilution calculations, which is

C₁V₁ = C₂V_2, where

1. C₁ is the concentration of the stock solution
2. V₁ is the volume you need to take from the stock solution
3. C₂ is the concentration of the target solution
4. V₂ is the concentration of the target solution

1) Starting with this formula, we rearrange the variables to isolate V₁ in order to solve for it, as it is the volume we are adding to the solution to get the desired concentration and volume

1. V₁ = (C₂V₂) / C₂

2) Plug in the values and solve

1. V₁ = (.337 M • .075 L) / 3 M

(Note 75 mL is converted to .075 L in order to have consistent units as M which is mol / L)

= .008425 L or .8425 mL