A student performs a gravimetric analysis to determine the mass percent of \(\text{Cl}^-\) in a solid mixture containing \(\text{NaCl}\) and unreactive water-soluble impurities. The student dissolves a sample of the mixture in distilled water, adds an excess of \(0.20 \text{ M } \text{AgNO}_3\text{(aq)}\) to precipitate all chloride ions as \(\text{AgCl(s)}\), collects the precipitate by vacuum filtration, and dries the precipitate to constant mass. The experimental data are recorded in the table below.

Measurement	Mass
Mass of unknown mixture sample	\(1.000 \text{ g}\)
Mass of dry filter paper	\(0.850 \text{ g}\)
Mass of filter paper \(+\) dry \(\text{AgCl(s)}\)	\(2.284 \text{ g}\)

Based on the data collected, what is the mass percent of \(\text{Cl}^-\) in the original sample, and how would failing to rinse the precipitate with distilled water before drying affect the calculated mass percent of \(\text{Cl}^-\)?