Question

You need to make an aqueous solution of 0.160 M cobalt(II) fluoride for an experiment in lab, using a 300 mL volumetric flask. How much solid cobalt(II) fluoride should you add?

Answer 1

To make a 0.160 M aqueous solution of cobalt(II) fluoride using a 300 mL volumetric flask, you should add 7.68 grams of solid cobalt(II) fluoride.

Step-by-step explanation:

Step 1: Calculate the number of moles of cobalt(II) fluoride needed to make the solution.

Molarity = moles of solute / liters of solution

0.160 M = moles of cobalt(II) fluoride / 0.3 L

moles of cobalt(II) fluoride = 0.160 M x 0.3 L = 0.048 moles

Step 2: Calculate the mass of cobalt(II) fluoride needed based on its molar mass.

The molar mass of cobalt(II) fluoride is:

CoF2 = 58.933 g/mol (cobalt) + 2 x 18.998 g/mol (fluorine) = 97.929 g/mol

Mass of cobalt(II) fluoride = moles of cobalt(II) fluoride x molar mass

Mass of cobalt(II) fluoride = 0.048 moles x 97.929 g/mol = 4.697 g

Step 3: Add the calculated mass of cobalt(II) fluoride to the volumetric flask, then add enough water to fill up to the 300 mL mark.

However, note that solid cobalt(II) fluoride may not be readily available in the lab, and proper safety measures should be taken when handling any chemicals.