2. 2mL of a 10M solution of Compound A is taken and 48mL added. 1mL of this solution is then taken and dried to dryness before being re-dissolved in 0.1mL. What is the concentration of the 0.1mL solution?

Answer 1

First dilution is 10M x (2/50) = 0.4M
You take 1 mL of that so you take moles = 0.4M x 0.001L = 4E-4 moles.
Then you dissolve that is 0.001 L so M = moles/L which is 4E-4/0.001 = ?M