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

Answer 1

1 Calculate the total number of moles of NaCl.

4.0 L x 1.5 mol L^-1 = 6.0 mol
2.0 L x 3.0 mol L^-1 = 6.0 mol

so total = 12.0 mol

2. Total volume = 6.0 L

3. New concentration = moles/volume

which I'll leave for you to do.