Question

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

I am confused about how to calculate the final concentration. We are currently working on solutions. I think first I need to divide the amount of the solution by the amount of the solute and then do the mass percent or do I use moles of a solute divided by L of solution?

Answer 1

Would it be volume divided by moles then convert to g

Answer 2

mols is the only way to go.
4.0 L x 1.5 M = ?? mols NaCl
2.0 L x 3.0 M = ?? mols NaCl.
Total mols NaCl/total L NaCl = M NaCl.