# Help Zone

### Student Question

How do I calculate the volume of solvent to add in a dilution? I am given an initial concentration (0.25 g / L), the volume (14 ml) and I want the final concentration (0.20 g / L).

Usually, I would use c1 * V1 = C2 * v2 to find the final volume, but I don't know which volume to add.

Can you help me?? Thank you

Science ## Explanations (1)

• Explanation from Alloprof  Explanation from Alloprof

This Explanation was submitted by a member of the Alloprof team.

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Team Alloprof • 9mo. edited September 2021

Hello!

You are on the right track!

Indeed, with the information provided in the question statement, you can find the final volume of solvent.

Since you can calculate the final volume of the solution and you know the initial volume, you can calculate the volume to add by calculating the variation in volume.

This formula expresses this variation:

$$V_{to\ add} = V_{final} - V_{initial}$$

Do not hesitate to come back to us if you have any other questions!