Molarity calculation

Suppose 2.71g of zinc chloride is dissolved in 350.mL of a 56.0mM aqueous solution of potassium carbonate. Calculate the molarity of zinc cation in the solution when it comes to equilibrium. You can assume the volume of the solution doesn't change when the zinc chloride is dissolved in it. Round your answer to 1 significant digit.

find moles, using molar mass:
2.71 g ZnCl2 @ 136.32 g ZnCl2 / mole = 0.01988 moles Zn+2

find moles
0.350.L @ 0.0560 moles / Litre = 0.0196 moles (CO3)-2

by the equation
Zn+2 & CO3)-2 --> ZnCO3 (s)
0.0196 moles (CO3)-2 reacts with an equal 0.0196 moles Zn+2 ,
0.01988 moles Zn+2 - 0.0196 moles Zn+2 reacted = 0.00028 moles Zn+2 remain

find molarity remaining
0.00028 moles Zn+2 / 0.350 litres = 0.000799 Molar
your answer, to 1 sig fig is
0.0008 Molar Zn+2
aka
0.8 milliMolar Zn+2


so