Question

A stock standard of urea nitrogen contains 20 mg/mL of urea nitrogen. How much stock is needed to prepare 100 mL of a 20 mg/dL working standard?

Please help!

Answer 1

20 mg/mL = 2000 mg/dL
c1v1 = c2v2
2000*x = 20*100
Solve for x. add that to a 100 mL volumetric flask, add distilled H2O to the mark on the flask, mix thoroughly.

Answer 2

Thank you!