The chelate CuQ2- exhibits max absorbance at 580nm. When chelating agent is present in 5 fold excess , the absorbance is dependent only upon the concentration of Cu and obeys beer law over a wide range.

Neither Cu or Q absorbs at 580nm.

A solution that is 1.40 x 10-4 M in Cu2+ and 6.20 x 10-4 M in Q2- has an absorbance of 0.580 in a 1.00 cm cell at 580 nm. Under the same conditions, a solution that is 1.40 x 10-4 M in Cu2+ and 3.00 10-4 M in Q2 has an absorbance of 0.410.

Calculate the formation constant for the process.

 

Cu2+ + 2Q <> CuQ2,

 

 

Think it has something to do with beer additive law and perhaps simultaneous equations. If someone could help me out on this I would greatly appreciate it. With explanation as well if possible.

 

Regards

 

Thomas

 

Note the subscripts didnt come out right when I posted it.

anyone?