How to calculate the concentration of an aqueous solution (in mol/L)

Take the number of moles of solute you have, divide it by the number of litres of water it's dissolved in... The clue is in the units.

If you have a more specific problem. Please ask and I can help you further.

Hey howe do u do this problem

When 28 mL of a 395 mL stock solution containing 1.8999999999999997 M AlCl3 is diluted to 70 mL, what is the concentration of Cl- in the new solution?