PLease show me how to do this 3 You are making 100mL of a bu

PLease show me how to do this

3.         You are making 100mL of a buffer that contains 150mM of NaCl. How would you dilute your 5M stock solution of NaCl to accomplish this? Show your calculations.

Solution

In this complication, the % solution is the number of grams solute in 100 ml solvent, so a 10% solution of NaCl is 10 grams NaCl in 100 ml water. But you need 500 ml, final volume, so 10 g x 5 = 50 g NaCl.

1:5 dilution = 1/5 dilution = 1 part sample and 4 parts diluent in a total of 5 parts. If you need 10 ml, final volume, then you need 1/5 of 10 ml = 2 ml sample. To bring this 2 ml sample up to a total volume of 10 ml, you must add 10 ml - 2 ml = 8 ml diluent.