Question

How do I calculate the concentrations for my data sheet lab. I have not started my lab yet but I just need to see how i would calculate it with absorbance. Do i just use Beer's law or is there any other method of solving the concentrations.

7. Weigh 1.45-1.55 g of copper(I) sulfate pentahydrate in a 50 mL beaker. 8. Dissolve the copper(II) sulfate pentahydrate in -15 mL of water 9. Add the aqueous solution of copper(II) to a 100.00 mL volumetric flask 10. Weigh 7.4-7.6 g of potassium sodium tartrate tetrahydrate in a 50 mL beaker. 11. Dissolve the potassium sodium tartrate tetrahydrate into -25 mL of distilled water 12. Add the aqueous solution of potassium sodium tartrate to the aqueous copper(II) solution 13. Rinse both beakers with small amounts of I M sodium carbonate solution and add to the 100 mL volumetric flask. After both beakers are rinsed twice, continue diluting the mixture in the 100.00 mL volumetric flask with I M sodium carbonate solution up to the mark. Cover the opening of the volumetric flask with parafilm, and mix thoroughly by inverting the flask. 14. Weigh 0.48-0.52 g of aspartame in a 50 mL beaker. 15. Dissolve the aspartame in minimal distilled water and pour the solution into a 100.0 mL. 16. Rinse the beaker three times with -10 mL of distilled water and pour into the volumetric flask. volumetric flask. 17. Fill the volumetric flask to the line with distilled water, cover with parafilm and mix 18. Prepare a standard solution of aspartame by dissolving the 500 mg of aspartame into 100.0 mL Part D. Sw thoroughly by inverting the flask. of water in a volumetric flask. tablets in a clean, dry beaker and using a digital pipette, add 16.00 mL of water 20. Using a digital pipette add 4.00 mL. of the copper(II) solution to the test ube. 21. Stir the mixture in the beaker. If the tablet does not completely dissolve after five minutes, you will need to use gravity filtration before taking measurements of the solution. a. The gravity filtration setup is shown in Figure 5. b. Pour the mixture of solid and solution through the fluted filter paper in the funnel. DO NOT RINSE the filter paper for this gravity filtration. Collect the filtrate. c.

Answer 1

Yes, you just use Beer's law to calculate the concentration, as shown below.

A = $\epsilon$ cl

Where A is the absorbance of the solution (which will be given in the problem).

$\epsilon$ is the molar extinction coefficient of the medium (constant value expressed in M^-1 cm^-1).

'C' is the concentration of the solution (in M)

'l' is the Pathlength = 1 cm