Question

What is the concentration of iron(II) sulfate in a 20 mL sample solution that has an absorbance of 0.45 at 562 nm, given that the molar extinction coefficient of iron(II) sulfate at that wavelength is 7,590 M^-1cm^-1?

Answer 1

To find the concentration of iron II  sulfate in the solution, we can use the Beer-Lambert Law:A =  * c * lwhere A is the absorbance  0.45 ,  is the molar extinction coefficient  7,590 M^-1cm^-1 , c is the concentration of the solution  which we want to find , and l is the path length of the cuvette  usually 1 cm .Rearranging the equation to solve for c:c = A /   * l Now, plug in the given values:c = 0.45 /  7,590 M^-1cm^-1 * 1 cm c = 0.0000593 MThe concentration of iron II  sulfate in the 20 mL sample solution is 0.0000593 M  or 59.3 M .