Question

Ringer's solution, used in the treatment of burns and wounds, is prepared by dissolving 8.6 g of NaCl, 0.30 g of KCl, and 0.33 g of CaCl2 in water and diluting to a volume of 1.00 L.

A. What is the molarity of NaCl?

B. What is the molarity of KCl?

C. What is the molarity of CaCl2?

Answer 1

Let us calculate the number of moles of each species in 1.00 L. The molecular weight of NaCl, KCl and CaCl2 are 58.44 g/mol, 74.55 g/mol and 110.98 g/mol, repsectively.

A) Number of moles of NaCl = Weight of NaCl in g / Molecular weight in g/mol

= 8.6 g / 58.44 g/mol

= 0.147 M

The molarity of NaCl is 0.147 M.

B) Number of moles of KCl = Weight of KCl in g . Molecular weight of KCl in g/mol

= 0.30 g / 74.55 g/mol

= 0.040 M

Therefore, the molarity of KCl is 0.040 M

C) The number of moles of CaCl2 = Weight of CaCl2 in g / molecular weight of CaCl2 in g/mol

= 0.33 g / 110.98 g/mol

= 0.00297 M

Therefore, the molarity of CaCl2 is 0.00297 M