Average human blood serum contains 18 mg of K+ Calculate:

Question

a) the molar concentration for each of these species; use 1.00 g/mL for the density of serum.

I have worked as of this
(18 mg K+/100 mL)(1mL/1g)(1 mmol/39.10mg)(1g/1000mg).
But it seems that some units are not cancelled out when the desired units should be mol/liters for molar conc.

Please help me, any ideas

Answer 1

18 mg/100 mL x (1000 mL/1L) x (1 g/1000 mg) x (1 mL/1 g) x (1 mol/39.1 g) = ? mols/L