The molar absorptivity based on chromium concentration is measured at max=540 nm using a photometer. For the calibration of the equipment, an experiment was conducted and results were presented below in the table based on absorbance values against Cr (VI) standard concentrations. After sample preparation of a surface water matrix, a 100mL sample was prepared. Then a measurement was carried out using 100mL sample and 0.34 absorbance value was obtained. Calculate the Cr concentration as mg/L based on the calibration values of the table