Question

A solution contains 0.625 g of Ca2 in enough water to make a 1930 mL solution. What is the concentration in milliequivalents per liter (mEq/L)?

Answer 1

Molar mass of Ca2+ = 40 g/ mol

Equivalent weight of Ca2+:

The weight of one equivalent can be determined by dividing the gram-atomic weight of the ion by its valence.

For calcium:

(40 g/ mol ) / (2 eq/ mol) = 20 g / eq

Now calculate the total number of equivalent in 0.625 g

0.625 g / 20 g / eq= 0.03125 eq.

1 equivalent = 1000 milliequivalent

0.03125 eq * 1000 milliequivalent/ equivalent =31.25 milliequivalent

1000 mL = 1.0 L

1930 mL = 1.930 L

The concentration in milliequivalents per liter (mEq/L):

31.25 milliequivalent / 1.930 L

=16.19 milliequivalents per liter (mEq/L)

16.2 milliequivalents per liter (mEq/L)