In the Spectrophotometric determination of Co (II) experiment, %T for a solution
ID: 527218 • Letter: I
Question
In the Spectrophotometric determination of Co (II) experiment, %T for a solution of CO(NO_3)_2. 6H_2O was measured at a series of different wavelengths. Use the data given below to determine the Absorbance values at these wavelengths and suggest the best wavelength that should be used for the experiment. (A = 2 - log %T) Wavelength _______ (i) If 6.5 g of Co(NO_3)_2 .6H_2O was dissolved in 250 mL deionized water, to prepare the stock solution, calculate the molarity of the solution. (ii) How do you prepare the following diluted solutions using the above stock solution. (a) 50 mL of 0.02 M solution b) 50 mL of 0.04 M solutionExplanation / Answer
Question 5
We will fill the table using the given formula:
A = 2 - log%T
Just remember this is a base 10 log and not a natural log.
Ideally, we want to use the wavelenght with the highest absorption, or absorbance (in other words, the one with the lowest %T), so according to the data we want to use the 510nm wavelenght.
nm 470 490 500 510 520 540 580 %T 67.2 68.9 66.2 56.7 57.6 68.2 90.2 A 0.173 0.162 0.179 0.246 0.240 0.166 0.045