Assume that you have 1, 2, 5, and 10 mL pipets and a 25 mL volumetric flask. Des
ID: 477872 • Letter: A
Question
Assume that you have 1, 2, 5, and 10 mL pipets and a 25 mL volumetric flask. Describe in detail how you would prepare a solution with a concentration near o.100 M from a 0.650 M stock solution. Calculate the final concentration of the diluted solution (it won't be exactly o.100 M). It should be within 10% of 0.100 M. (Please see the Lab skills for the accuracy on volumetric pipets and flasks.) Predict the color of a solution of a food coloring dye that has the visible light absorption spectrum shown below. What wavelength would be best for monitoring the concentration of this dye? Give at least two reasons why this wavelength would be best.Explanation / Answer
1. Preparation of solutions,
25 ml of 0.1 M from 0.65 M
volume of 0.65 M to be taken = 0.1 x 25/0.65 = 3.8 ml
So we would take 3 ml using 5 ml pipetter and 0.8 ml using 1 ml pipette and dilute it with 21.2 ml water using 10 ml and 1 ml pipette.
2. The color corresponding to the 450 nm wavelength max would be yellow. We observe highest absorption at this wavelength for the solution and thus this is best.