Question

Suppose 3.67g of zinc chloride is dissolved in of a 68.0mm aqueous solution of potassium carbonate. Calculate the final molarity of chloride anion in the solution?

Answer 1

The final molarity of chloride anion after dissolving 3.67g of zinc chloride in a 68.0mm aqueous solution is 0.791 M. This is calculated by finding the moles of zinc chloride, doubling it for chloride ions, and dividing by the volume in liters.

Step-by-step explanation:

Calculating the Final Molarity of Chloride Anion

To calculate the final molarity of chloride anion in the solution after dissolving 3.67g of zinc chloride, we need to follow these steps:

1. Calculate the number of moles of zinc chloride (ZnCl2) using the formula:
   n = mass (g) / molar mass (g/mol).
2. Since ZnCl2 dissociates into Zn2+ and 2Cl− ions in water, the moles of Cl− will be twice that of ZnCl2.
3. Divide the total moles of Cl− by the volume of the solution in liters to find the molarity (M).

The molar mass of ZnCl2 is approximately 136.3 g/mol. So, we have:

• Number of moles of ZnCl2 = 3.67 g / 136.3 g/mol = 0.0269 moles.
• Moles of Cl− = 2 × 0.0269 moles = 0.0538 moles.
• The volume of the solution is 68.0 mm, which is equal to 0.0680 L.
• The molarity of Cl− = 0.0538 moles / 0.0680 L = 0.791 M.

Therefore, the final molarity of chloride anion in the solution is 0.791 M.