A solution of sodium (Na⁺,atomic weight = 23)and a solution of calcium (Ca²⁺,atomic weight = 40)have equal mg%.The mEq/L of calcium would be about _____ that of sodium.

Question

Quizplus · Accepted Answer

The molecular weight of Na⁺ is 23, while that of Ca²⁺ is 40. Therefore, to have equal mg%, the molar amount of Ca²⁺ would be (23/40) times that of Na⁺.
mEq/L is a measure of the concentration of ions in a solution. To calculate the mEq/L of each ion, we need to divide the mg% by its molecular weight, and then adjust for the charge of the ion.
For Na⁺: mEq/L = (mg% / 23) / 1 = mg% / 23
For Ca²⁺: mEq/L = (mg% / 40) / 2 = (mg% / 80) x 2
Since the mg% is the same for both solutions, we can compare the mEq/L directly:
mEq/L(Ca²⁺) / mEq/L(Na⁺) = [(mg% / 80) x 2] / (mg% / 23) = 23 / 40 x 2 = 46 / 40
Therefore, the mEq/L of calcium would be about twice that of sodium.

A Solution of Sodium (Na⁺,atomic Weight = 23)and a Solution