Calculate the final concentration if 4.0 L of 1.5 M NaCl and 2.0 L of 3.0 M NaCl are mixed?

4.0 L x 1.5 M = ?? moles from solution A.

2.0 L x 3.0 M = ?? moles from solution B.

Total moles = moles A + moles B.
Then total moles/total L (6.0 L) = molarity of the mixed solution.

To calculate the final concentration when two solutions are mixed, you need to use the formula:

C1V1 + C2V2 = CfVf

Where:
C1 and C2 are the initial concentrations of the solutions
V1 and V2 are the initial volumes of the solutions
Cf is the final concentration
Vf is the final volume

In this case, we have:
C1 = 1.5 M (concentration of the first solution)
V1 = 4.0 L (volume of the first solution)
C2 = 3.0 M (concentration of the second solution)
V2 = 2.0 L (volume of the second solution)

Now let's plug these values into the formula and solve for Cf:

(1.5 M)(4.0 L) + (3.0 M)(2.0 L) = CfVf

6.0 + 6.0 = CfVf

12.0 = CfVf

To get the final concentration, we divide both sides of the equation by the final volume (Vf):

Cf = 12.0 / Vf

Therefore, the final concentration (Cf) depends on the final volume (Vf). If you know the final volume, you can plug it into this equation to calculate the final concentration.