Answer: The dilution formula is V1M1 = V2M2. We need 3 of the values to calculate the 4th. We have the original volume (2 mL of copper ion solution) and the final volume (20 mL), but we don't have the concentration of either the original or the final copper solution, All we can say is the resulting solution is 10 times as dilute as the original was- V1M1 = V2M2 2Ă—0.200 = 20Ă—M2, so M2 = 0.400/20 = 0.020M