In a student experiment, the empirical formula of a copper halide was found by adding aluminum metal to an aqueous solution of the halide. displacing copper metal. The copper metal was filtered, washed with distilled water, dried, and weighed: three separate determinations were performed. The copper halide solution contained 42.62 g of copper chloride per liter. The student recorded the following experimental data. Write the empirical formula of copper chloride based on the experimental data. Express your answer as a chemical formula.