Chemistry mol/L

Question

A chemist prepares a solution of mercury(II) iodide HgI2 by measuring out 4.02mg of mercury(II) iodide into a 250. mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in mol/L of the chemist's mercury(II) iodide solution. Round your answer to 3 significant digits.

Answer 1

Molar mass HgI₂ = 454 g / mole

To find moles / liter, first we will find the moles of HgI₂:

moles HgI₂ = 4.02 mg x 1 g / 1000 mg x 1 mol / 454 g = 8.85x10^-6 moles

Next we convert 250 ml to liters:

250 ml x 1 L / 1000 ml = 0.250 L

Finally, we divide the moles by the liters to get moles / liter:

8.95x10^-6 mols / 0.250 L = 3.54x10^-5 mols / L