Question

Suppose 2.57g of nickel(II) chloride is dissolved in 350.mL of a 38.0mM aqueous solution of potassium carbonate.

Answer 1

Answer:

Molarity Ni^2+ = 0.0566 M

Explanation:

Step 1: Data given

Mass of nickel(II) chloride = 2.57 grams

volume of an aqueous 38.0 mM solution of potassium carbonate = 350 mL =0.350 L

The molar mass of nickel (II) chloride = 129.6 g/mol

Step 2: The balanced equation

NiCl2(aq) + K2CO3(aq) → 2KCl(aq) + NiCO3(s)

The dissociation of nickel (II) chloride:

NiCl2 →  Ni^2+ + 2Cl-

Step 3: Calculate moles NiCl2

Moles NiCl2 = mass NiCl2 / molar mass NiCl2

Moles NiCl2 = 2.57 grams / 129.6 g/mol

Moles NiCl2 = 0.0198 moles

For 1 mol NiCl2 we have 1 mol Ni^2+

For 0.0198 moles NiCl2 we have 0.0198 moles Nickel(II) cation

Step 4: Calculate molarity Ni^2+

Molarity Ni^2+ = moles / volume

Molarity Ni^2+ = 0.0198 moles / 0.350 L

Molarity Ni^2+ = 0.0566 M