A chemist adds of a M mercury (II) iodide solution to a reaction flask. Calculate the mass in milligrams of mercury (II) iodide the chemist has added to the flask. Round your answer to significant digits.

0.42 mg

Explanation:

It seems the question is incomplete, however I'll use values that have been found in a web search:

"A chemist adds 55.0 mL of a 1.7x10⁻⁵ M mercury (II) iodide solution to a reaction flask. Calculate the mass in milligrams of mercury (II) iodide the chemist has added to the flask. Round your answer to 2 significant digits."

Keep in mind that while the process of solving the problem remains the same, if the values in your question are different, your answer will differ as well.

First we calculate the moles of mercury (II) iodide (HgI₂):

1.7x10⁻⁵M * 55.0 mL = 9.35x10⁻⁴ mmol HgI₂

Then we convert mmol to mg, using the molar mass (454.4 g/mol):

9.35x10⁻⁴ mmol HgI₂ * 454.4 mg/mmol = 0.42 mg