Hi Amanda. Please don't freak out! It's not as hard as it looks! If I assume your question correctly, you are asking 'how many grams of NaOH are required to make 505 mL of .10 M NaOH', correct?
To do that, you find out how many total moles you. .10 M is the same as .10 moles/L, so we need to convert you volume from milliliters to liters. 505 mL = .505 L. So, you multiply .505 L * .10 mol/L, and you get .0505 moles. Now, you know the molecular weight of NaOH is approx. 40 g/mol, so you do .0505 mol * 40 g/mol, and you get 2.02 g, which is your final answer. Hope this helps!
