3. When 30 mL of a 375 mL stock solution containing 2.11 M AlCl3 is diluted to 92 mL, how many moles of Al3+ are in the new solution?
4. A stock solution is prepared by adding 35 mL of 1.5 M NaNO2 to enough water to make 49 mL. How many moles of NO2- are in 30 mL of the stock solution?