An IV requires the addition of 40 mEq of potassium chloride. You have a vial of KCI at a concentration of 20 mEq per 10 mL. How many mL should be added?

Question

Could someone help me with this problem.  My professor is not explaining this properly.  He wants it set up in an algebraic expression and not showing me how to do it?  I will understand once someone shows me how to set it up.

 

Answer 1

The stock solution is 20 mEq/10 ml.  Dividing 20/10 = 2 mEq/1 ml.  If 1 ml is 2 mEq, then 2 ml is 4 mEq and so on. So, you'd need 20 ml.   Mathematically, you can set it up as follows:

20 mEq/10 ml = 40 mEq/x ml

Cross multiplying:  20x = 400

x = 20 ml