Exp. 1 - Experiment 1 lab report PDF

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Experiment 1 lab report...

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Nadia Valencia Chem 201 Section # 6

INTRODUCTION TO THE SPECTROPHOTOMETER AND BEER’S LAW Pre-lab:

N Chem 201 Section # 6

Experiment/Procedure: ● Test tube 1 had DI water only; 0mL of stock solution ● Erioglaucine disodium: stock concentration is 7.7฀ 10−6 M ● Wavelengths of solutions 1-5 ● Solution 1: 635nm ○ Solution 2: 635nm ○ Solution 3: 635nm ○ Solution 4: 635nm ○ Solution 5: 635nm ● Absorbance of extra test tube with 5mL of dye: .913 Table 1: Solution # Amt. of stock solution (mL)

Amt. of DI water (mL)

Concentration (M)

Absorption

1

0

DI water only

0

0

2

1

4

1.54฀ 10−6

.16

3

2

3

3.08฀ 10−6

.316

4

3

2

4.62฀ 10−6

.481

5

4

1

6.16฀ 10−6

.688

6

5

0

7.7฀ 10−6

.903

Part A in the experiment was not done. Part B: I graphed the absorbance values versus the concentrations of the dye & stock solution. The slope of the trendline ( εl ) is 116215

N dia Valencia Chem 201 Section # 6

L/mol. The units of the trendline are in units of L/mol. Handwritten sample calculations:

Discussion: For part B we used 6 test tubes to measure the concentration and absorbance of the blue dye and stock solution. Test tube 1 had 0mL of stock solution and 5mL of DI water, with concentration of 0M and absorbance of 0.00. Test tube 2 had 1mL of stock solution and 4mL of DI water, with concentration of 1.54฀ 10−6 M and absorbance of 0.16. Test tube 3 had 2mL of stock solution and 3mL of DI, with concentration of 3.08฀ 10−6 M and absorbance of 0.316. Test tube 4 had 3mL of stock solution in it and 2mL of DI water, with 4.62฀ 10−6 M being the concentration and absorbance of .481. Test tube 5 had stock solution of 4mL and 1mL of DI water with the concentration being 6.16฀ 10−6 M and absorbance of .688. The last test tube, 6, had the maximum amount of stock solution being 5mL with 0mL of DI water. This concentration came to be 7.7฀ 10−6 M with an absorbance of .903. The εl value I calculated from using the graph I created was 116215 L/mol All my data was given to me because of the pandemic and distance learning. Seeing that the trendline goes through the origin (0,0), I can guess that if I were to perform this experiment in person it would not be linear since measurement errors would most likely have happened. Measurement error for the DI water and/stock solution would result in miscalculation. While watching my teaching assistant...