how much NaOH (in grams)do you need to weigh ouMt to make 250ml of a 0.5M naoh solution.... i got 5.0g is this right?
You need (1/4 l)* 0.5 mol/l = 1/8 moles of NaOH
1 mole of NaOH has a mass or 23 + 16 + 1 = 40 g.
1/8 of 40 is 5 g, so you are correct