Sterile solutions of potassium chloride containing 5 mEq/mL are available in 20 mL containers. How do you calculate the amount, in grams, of potassium chloride in the container.

Question

Rationale, and what is being asked.

Answer 1

Not sure if you mean 5 mEq KCl per ml or per liter. Normally, KCl is present at around 5 mM so that would be 5 mEq / L. Assuming you did mean 5 mEq / 20 ml, then ....

1 mEq of KCl = 1 mmol of KCl

5 mEq of KCl = 5 mmol KCl in the 20 ml container

molar mass of KCl = 74.6 g / mol = 74.6 mg / mmole = 0.0746 g / mmole

5 mmole KCl x 0.0746 g / mmole = 0.37 g of KCl in the 20 ml container (0.4 g rounded to 1 sig.fig.)

Hope that makes sense.