Question

You are asked to prepare 220 mL of a 3% morphine sulfate solution. You have four 50-mL vials of morphine sulfate labeled as 50 mg/mL. What are the volumes of stock solution and water you need? Express your answers using two significant figures.

Answer 1

3 % morphine means we have 3g of morphine per 100 ml solution

we need 220 ml solution , hence mass of morphine needed = ( 3g/100ml) x 220ml = 6.6 g = 6600 mg

we had solution of 50 mg/ml    solution

hence solution from vial taken = ( 6600 mg) x ( 1ml / 50 mg) = 132 ml ( rounded to two sig figures we get 130 ml) . Water volume = 220 -130 = 90

Thus we take 130 ml stock solution and we add   90 ml of water to make 220 ml of 3% morphine solution