[TTAGGGn]

I took UV-vis spectrums of pure Cr, pure Co, and also a mixture of Cr with Co.

The spectrometer spit out the data. I super imposed it on excel. So I have the absorbance and wavelengths. How do I determine the molar absorptivity of the pure Cr and pure Co?

A = (molar absorptivity) x (concentration) x (path length), which rearranges to

molar absorptivity = A / [(concentration) x (path length)]


I was not provided with the concentration so I have two variables to find (molar absorptivity and concentration).
am i suppose to look up the molar absorptivity from some where or do i calculate it? i know for sure that i will have to calculate the concentration

I was told to make the solutions from a stock solutions. here was the mixtures totaling 10mL

Co           Cr        
1mL             9mL
2mL             8mL
3mL             7mL
4mL             6mL
5mL             5mL
6mL             4mL
7mL             3mL
8mL             2mL
9mL             1mL

[Mitch]

The path length is usually a centimeter, but these are things you needed to have measured the day of the experiment. What was the concentration of the stock solution?

[TTAGGGn]

i dont think we were given the concentration of the stock solutions of the pure Cr or Co

and yes i know the cuvette was 1cm = 10mm

[Mitch]

I can't imagine figuring out the molar absorptivity without knowing the concentration of stock solution.

[TTAGGGn]

i guess i forgot to check/write down the stock solution concentration. ill check to see if i can still find the stock solution concnetration tomorrow

thanks for replying