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Secondaire 3 • 1m

Good evening,


Can you show me how to solve a complete dilution problem? I have a lot of difficulty with that!

Science
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Explications (1)

  • Explication vérifiée par Alloprof
    Enseignant Alloprof • 1m

    Thank you for your question!


    First off, diluting a solution is essentially decreasing the concentration of its solute by adding solvent. It goes without saying that the final concentration of a dilute solution is less than the initial concentration of this solution.


    The following formula is used when executing dilution calculations:

    $$C_{1} • V_{1} = C_{2} • V_{2}$$

    Legend:

    • C1: initial concentration of the solution

    • V1: initial volume of the solution

    • C2: final concentration of the solution

    • V2: final volume of solution


    Several units can be used to describe the concentration and volume of a solution in the dilution formula. As long as the units are the same on both sides of the equation, the formula works.


    Most dilution problems start off with 3 of the 4 variables in the equation. Algebraic manipulation subsequently allows to isolate the missing value:

    $$C_{1} = \frac{C_{2} • V_{2}} {V_{1}}$$

    $$V_{1} = \frac{C_{2} • V_{2}}{C_{1}}$$

    $$C_{2} = \frac{C_{1} • V_{1}}{V_{2}}$$

    $$V_{2} = \frac{C_{1} • V_{1}}{C_{2}}$$


    Some problems require finding a volume of solution to add. In this case, you have to remember the following formula:

    $$V_{final} = V_{initial} + V_{to_add}$$

    Simply modifying the expression of the above equation allows to find the volume of solvent to add:

    $$V_{to_add} = V_{final}− V_{initial}$$


    There you go! Let us know if we can do anything else to help!