Question

What is the concentration of iron (II) ions in a solution if the absorbance reading from the colorimeter is 0.43 and the path length of the solution in the cuvette is 1 cm? The molar absorption coefficient of iron (II) ions is 6.16 x 10^3 M^-1 cm^-1. The solution has a volume of 10 mL. Calculate the concentration of iron (II) ions in the solution in units of Molarity.

Answer 1

To calculate the concentration of iron  II  ions in the solution, we can use the Beer-Lambert Law, which states:A =  * c * lwhere A is the absorbance,  is the molar absorption coefficient, c is the concentration of the solution, and l is the path length of the solution in the cuvette.We are given the following values:A = 0.43  absorbance  = 6.16 x 10^3 M^-1 cm^-1  molar absorption coefficient l = 1 cm  path length We need to solve for c  the concentration of iron  II  ions in the solution .Rearranging the Beer-Lambert Law equation to solve for c:c = A /   * l Now, plug in the given values:c = 0.43 /  6.16 x 10^3 M^-1 cm^-1 * 1 cm c = 0.43 /  6.16 x 10^3 c  6.97 x 10^-5 MTherefore, the concentration of iron  II  ions in the solution is approximately 6.97 x 10^-5 M.