Question

A chemist adds 265.0 mL of a 0.0032 mM copper(II) fluoride (CuF2) solution to a reaction flask. Calculate the mass in micrograms of copper(II) fluoride the

chemist has added to the flask. Round your answer to 2 significant digits.

Answer 1

86 μg

Step-by-step explanation:

First, we have to calculate the molar mass (MM) of copper(II) fluoride (CuF₂) from the molar mass of its elements:

MM(CuF₂) = MM(Cu) + (2 x MM(F)) = 63.5 g/mol + (2 x 19 g/mol)= 101.5 g/mol

Then, we calculate the number of moles of CuF₂ there is in 265.0 mL of a 0.0032 mM solution:

0.0032 mM = 0.0032 mmol/L

265.0 mL x 1 L/1000 mL = 0.265 L

0.0032 mmol/L x 0.265 L = 8.48 x 10⁻⁴ mmol

Now, we have to convert from mmol to grams by using the molar mass of CuF₂. The molar mass can be expressed in g/mol or mg/mmol. We multiply the number of mmol by the molar mass in mg/mmol to obtain the mass in mg:

8.48 x 10⁻⁴ mmol x 101.5 mg/mmol = 0.086072 mg

Finally, we use the relation: 1000 μg = 1 mg, to convert the mass from mg to micrograms (μg):

0.086072 mg x 1000 μg/1 mg = 86.072 μg ≅ 86 μg