The document discusses an experiment where known and unknown samples were treated and their absorbance measured at 540nm using a photometer. The absorbance readings for known concentrations of nitrite allow for the determination of the nitrite concentration in the unknown sample, which has an absorbance of 0.09. Based on the provided data, the nitrite concentration of the unknown sample can be calculated.

1. Several known samples and an unknown sample were treated and the color was measured with a
photometer. Find the nitrite concentration in mg/L of the unknown sample
NO2 Concentration(mM/L). ABS @ 540nm
0 0
5. 0.02
10 0.04
20 0.06
40 0.12
Unknown sample ABS = 0.09