Question

If you add 90 mL of 0.15M stock solution, to 10 mL of water, what is the new concentration?

Answer 1

0,15 moles of NaOH-------in------------1000ml

x moles of NaOH------------in--------100ml

x = 0,015 moles of NaOH

final volume = 150ml

0,015 moles of NaOH---in-------150ml

x moles of NaOH--------------in-----1000ml

x = 0,1 moles of NaOH

answer: 0,1mol/dm³ (molarity)