concentrations/ mixing

[recon9]

Ok, Im trying to remember my grade 11 chem stuff cause Im helping out a friend who is taking it, but When you have 2 samples of the same chemical, different volumes and different concentrations then mix them, what formula is used to find the final concentration? is it CiVi + CiVi= CfVf ?

[sven222]

C1V1 = C2V2

[recon9]

Thats for dilution. In this question I have 2 samples of the same substance each with a different volume and concentration. Those are then mixed. How do I find the total concentration of the mixture? The final volume will be the sum of the 2 volumes before, but the concentration will be different.

[chem_tr]

I got it now. You may use this then:
\frac {C_1V_1+C_2V_2}{V_1+V_2}
This will give the final concentration after two solutions are mixed. But please remember that the final concentration will be less than each of the two, as two solutions are mixed; so a dilution approach would not be incorrect, unless one of the participants is solvent-free.