An unknown Chromium solution was mixed with aliquots of a standard solution of Chromium for atomic absorption spectroscopy. The standard solution contained 1000 ppm of Chromium (this is [s]i)

Volume of unknown (mL) Volume of Standard (mL) Total Volume (mL) Absorbance
10 0 100 .163
10 1 100 .240
10 2 100 .319
10 3 100 .402
10 4 100 .478

(a) Calculate the concentration (ppm) of added standard in each solution i.e. [S]f