Concentration of Cu in a sample can be determined by its reaction with the ligand cuprizone to form a color complex that absorbs light at 606 nm. The concentration of Cu2+ was determined by mixing 20.0 mL sample with 20.0 mL of cuprizone solution. The resulting solution was diluted to 100.0 mL and analyzed by absorption spectroscopy using calibration curve from standards. The results for the analysis are shown in the following table. Determine Cu2+ concentration in the sample ( DO NOT USE EXCEL)

Solution	ppm Cu2+	Absorbance
Blank	0	0.005
standard 1	0.200	0.012
standard 2	0.500	0.035
standard 3	1.000	0.070
standard 4	2.000	0.145
sample		0.055