Submission page for Performance task 3 As you read throug

Homework answers / question archive / Submission page for Performance task 3 As you read through the lab, answer the following questions: Qualitative relationships: What is the relationship on the amount of transmitted light vs absorbed light concerning: a) Thickness of the container (tube)? b) Concentration of the sample? c) Color of the sample? d) The specific chemical in the solution? Quantitative Relationships between absorbance vs wavelength: wavelength Absorbance of sample A Absorbance of sample B 400 nanometers 0

Submission page for Performance task 3 As you read through the lab, answer the following questions: Qualitative relationships: What is the relationship on the amount of transmitted light vs absorbed light concerning: a) Thickness of the container (tube)? b) Concentration of the sample? c) Color of the sample? d) The specific chemical in the solution? Quantitative Relationships between absorbance vs wavelength: wavelength Absorbance of sample A Absorbance of sample B 400 nanometers 0

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Submission page for Performance task 3

As you read through the lab, answer the following questions:

Qualitative relationships:

What is the relationship on the amount of transmitted light vs absorbed light concerning:

a) Thickness of the container (tube)?

b) Concentration of the sample?

c) Color of the sample?

d) The specific chemical in the solution?

Quantitative Relationships between absorbance vs wavelength:

wavelength	Absorbance of sample A	Absorbance of sample B
400 nanometers	0.173	0.600
420 nanometers	0.202	0.451
440 nanometers	0.282	0.050
460 nanometers	0.650	0.310
480 nanometers	0.920	0.522
500 nanometers	1.150	0.750
520 nanometers	1.230	1.10
540 nanometers	0.885	1.21
560 nanometers	0.458	1.32
580 nanometers	0.300	1.15
600 nanometers	0.066	0.90

What is your independent vs dependent variables?

Graph both sets of data on the graph paper below:

The color of the solution can be determined by the lowest absorbance for that wavelength. (remember, these wavelengths are in nanometers vs meters from your electromagnetic spectrum)

What would be the color of Solution A?

What would be the color of Solution B?

Determining the absorbance of known concentrations for Solution A:

What is the most sensitive wavelength for Solution A (meaning highest absorbance) ______. Using this wavelength, we now place known concentrations of Sample A in the Spec 20 machine and see the absorbances.

Sample A concentrations	Absorbance using Spec 20 instrument
0.000Molar (distilled water)	0.000
0.020 Molar	0.150
0.050 Molar	0.382
0.100 Molar	0.550
0.150 Molar	0.950
0.200 Molar	1.230

What is the independent & dependent variables?

What variables go on what axis?

Graph the sample concentrations vs the absorbances on the graph paper below:

Does this a direct or inverse relationship?

Is this graph more linear or nonlinear?

Determining the concentration of an unknown sample using the standard curve from above.

Last initial	Unknown #	Absorbance	Concentration from the graph
054, 799, 119	A-6	0.800
760, 563, 219	N-2	0.720
823, 015, 094, 329	L-5	0.650
317, 491, 556, 585	Y-4	1.150
168, 181, 968, 036	T-8	0.850
790, 193, 791, 373	M-12	0.960

Application question using the Spec 20 machine:

You want to determine if the toxic metal Lead (Pb) was in your drinking water and if the concentration was a high enough Molarity to cause health problems. Using the Spec 20 instrument, how would you set up a procedure to identify the metal and determine the concentration?

Transmittance vs Absorbance

Block the light beam with your hand to verify that the CBL responds rapidly by dropping radically in value. If it does not, check with your instructor before proceeding.