Ringer's solution, used in the treatment of burns and wounds, is prepared by dissolving 4.30 g of NaCl, 0.150 g of KCl, and 0.165 g of CaCl2 in water and diluting to a volume of 500.0 mL. What is the molarity of each of the component ions in the solution?

Verified step by step guidance

1. First, we need to calculate the number of moles of each salt. The number of moles is calculated by dividing the mass of the substance by its molar mass. The molar mass of NaCl is approximately 58.44 g/mol, of KCl is approximately 74.55 g/mol, and of CaCl2 is approximately 110.98 g/mol.
2. Next, we calculate the volume of the solution in liters, since molarity is defined as moles of solute per liter of solution. In this case, the volume is 500.0 mL, which is equivalent to 0.500 L.
3. Then, we calculate the molarity of each salt by dividing the number of moles of each salt by the volume of the solution in liters. This will give us the molarity of NaCl, KCl, and CaCl2.
4. Remember that each salt dissociates into its component ions in solution. NaCl dissociates into Na+ and Cl-, KCl dissociates into K+ and Cl-, and CaCl2 dissociates into Ca2+ and 2 Cl-. Therefore, the molarity of the Cl- ion will be the sum of the molarities of each salt.
5. Finally, we have the molarity of each of the component ions in the solution. The molarity of Na+ is the same as the molarity of NaCl, the molarity of K+ is the same as the molarity of KCl, the molarity of Ca2+ is the same as the molarity of CaCl2, and the molarity of Cl- is the sum of the molarities of NaCl, KCl, and CaCl2.

Key Concepts

Molarity

Molarity is a measure of concentration defined as the number of moles of solute per liter of solution. It is expressed in moles per liter (mol/L) and is crucial for understanding how much of a substance is present in a given volume of solution. To calculate molarity, one must first determine the number of moles of each solute and then divide by the total volume of the solution in liters.

Dissociation of Ionic Compounds

Ionic compounds, such as NaCl, KCl, and CaCl2, dissociate into their constituent ions when dissolved in water. This dissociation is essential for calculating the molarity of each ion in the solution. For example, NaCl dissociates into Na⁺ and Cl⁻ ions, while CaCl2 dissociates into Ca²⁺ and two Cl⁻ ions, affecting the total concentration of ions in the solution.

Calculating Moles from Mass

To find the number of moles of a substance from its mass, one can use the formula: moles = mass (g) / molar mass (g/mol). Each component in Ringer's solution has a specific molar mass, which is necessary for converting the given masses of NaCl, KCl, and CaCl2 into moles. This step is fundamental for determining the molarity of each ion in the final solution.