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.

Ni2 Visible Spectra

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.

Table 9-1. Molar Absorptivity e, M 'cm 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

5.10

1.48

0.40

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:

0 -2

Responses

Post a comment