Question

Absorbance readings are taken for five standard ferrous (ii) thiocyanate solutions and a beer’s law plot is created with the equation: y = 3.2975x + 0.0021. a ferrous (ii) thiocyanate solution of unknown concentration is found to have an absorbance of 0.31. the cuvette was 1cm wide. what is the unknown concentration according to the above data?

Answer 1

The Beer's Law plot is a graph of Absorbance data vs Concentration data. The plot is linear which follows the slope-intercept form: y = mx + b, where m is the slope and b is the y-intercept. The y data is the absorbance, and the x data is for the concentration. At the same wavelength, this equation can be used to determine C at a given absorbance. When y = 0.31, then x is

0.31 = 3.2975x + 0.0021
Solving for x,
x = 0.0934

Thus, the unknown concentration is 0.0934 mol/L.