Suppose an EPA chemist tests a sample of groundwater known to be contaminated with copper(II) chloride, which would react with silver nitrate solution like this: (aq) (aq) (s) (aq) The chemist adds M silver nitrate solution to the sample until silver chloride stops forming. She then washes, dries, and weighs the precipitate. She finds she has collected of silver chloride. Calculate the concentration of copper(II) chloride contaminant in the original groundwater sample. Round your answer to significant digits.