## How To Calculate Uv Vis Spectra Excel

Answers to the following problems are found in the folder "Ch. 09 (Simultaneous Equations)" in the "Problems & Solutions" folder on the CD.

1. Solve the following system of four simultaneous equations:

2. Current flow in a circuit is described by Kirchhoffs laws. A particular circuit network yielded the following three simultaneous linear equations:

Find the currents I\I2 and /3 in the circuit network.

3. Solve the following system of four simultaneous equations:

2.829*, - 2.253*2 + 6.777*3 + 3.970*4 = 6.235 1.212*, + 1.995*2 + 2.265*3 + 8.008*4 = 7.319 4.553*1 + 5.681*2 + 8.850*3 + 1.302*4 = 5.730 5.808*i - 5.030*2 + 0.098*3 + 7.832*4 = 9.574

4. The UV-visible spectra of aqueous solutions of C0CI2, NiCl2 and CuCl2 are shown in Figure 9-16.

350 450 550 650 750

Wavelength, nm

Figure 9-16. UV-visible spectra of cobalt, nickel and copper solutions.

350 450 550 650 750

Wavelength, nm

Figure 9-16. UV-visible spectra of cobalt, nickel and copper solutions.

Three wavelengths were chosen at which the absorbance of the three species, Co2+, Ni2+ and Cu2+, differed significantly. The molar absorptivities of the three species at the three wavelengths are shown in Table 9-1.

 A,/nm Co2+ Ni2+ Cu2+ 394 0.995 6.868 0.188 510 6.450 0.215 0.198 808 0.469 1.179 15.052

A mixture of the three metal ions gave the following absorbance readings at the three wavelengths: 394 nm, 0.845; 510 nm, 0.388; 808 nm, 1.696, when measured using a cell with a 1.00-cm path length. Calculate the concentration of the three metal ions in the mixture, using Beer's Law: A = sbc (A = absorbance, e = molar absorptivity, b = cell path length in cm, c = concentration in mol/L).

5. The following sets of simultaneous equations may or may not be solvable by the Gaussian Elimination method. For each case, explain why. If solvable, solve.

2

-1 l"

"4"

(b)

1

3 2

12

3

2 3_

6. Solve the following system of six simultaneous equations:

 2.97 0.75 1.23 2.08 1.26 0 7.93 2.34 2.38 1.23 1.23 1.94 2.07 9.79 1.23 0.52 0 3.66 0.18 0.51 26.19 1.84 1.89 2.64 2.65 0.51 0.38 5.1 1.48 0.4 2.88 1.46 0 2.65 8.43 2.94 1.55 1.71 1.06 2.46 2.97 -15.74

7. Solve the following system of nonlinear equations:

8. Solve the following system of nonlinear equations: