Question

PRE-LAB QUESTIONS: 1) Calculate the volume of stock solution needed to prepare 50.0 mL of each of the standard solutions indicated below. Show all of your calculations (neatly). (1 point) Standard Solution #: 1, 2, 3, 4 Concentration of stock solution (M): 1.94 x 10^-4 M (for all) Volume of stock solution needed to prepare diluted standard solution (mL): (blank table) Final Volume of standard solution (mL): 50.0 mL (for all) Concentration of standard solution (M): 1: 3.87 x 10^-6 (M) 2: 9.70 x 10^-6 (M) 3: 2.91 x 10^-5 (M) 4: 3.87 x 10^-5 (M) 2) What range of wavelengths should be investigated with the spectrophotometer to determine the exact wavelength of maximum absorbance for the red dye? Use Table 2 on page 2, and report your answer using a complete sentence. (1 point) 3) What is molar absorptivity? How is it represented in the Beer-Lambert equation? What aspect of a standard curve reveals the molar absorptivity? (2 points) 4) Use the standard curve shown below (and the trendline equation included) to calculate the concentration of a sample that has a measured absorbance of 0.853 AU. What are the units for concentration in this specific example? (1 point) Standard Curve for Green Dye (? = 642 nm) y = 655.7x + 0.0129 R² = 0.99744 Concentration of Green Dye (g/mL)

          PRE-LAB QUESTIONS:

1) Calculate the volume of stock solution needed to prepare 50.0 mL of each of the standard solutions indicated below. Show all of your calculations (neatly). (1 point)

Standard Solution #: 1, 2, 3, 4
Concentration of stock solution (M): 1.94 x 10^-4 M (for all)
Volume of stock solution needed to prepare diluted standard solution (mL): (blank table)
Final Volume of standard solution (mL): 50.0 mL (for all)
Concentration of standard solution (M):
1: 3.87 x 10^-6 (M)
2: 9.70 x 10^-6 (M)
3: 2.91 x 10^-5 (M)
4: 3.87 x 10^-5 (M)

2) What range of wavelengths should be investigated with the spectrophotometer to determine the exact wavelength of maximum absorbance for the red dye? Use Table 2 on page 2, and report your answer using a complete sentence. (1 point)

3) What is molar absorptivity? How is it represented in the Beer-Lambert equation? What aspect of a standard curve reveals the molar absorptivity? (2 points)

4) Use the standard curve shown below (and the trendline equation included) to calculate the concentration of a sample that has a measured absorbance of 0.853 AU. What are the units for concentration in this specific example? (1 point)

Standard Curve for Green Dye (? = 642 nm)
y = 655.7x + 0.0129
R² = 0.99744
Concentration of Green Dye (g/mL)

PRE-LAB QUESTIONS:

1) Calculate the volume of stock solution needed to prepare 50.0 mL of each of the standard solutions indicated below. Show all of your calculations (neatly). (1 point)

Standard Solution #: 1, 2, 3, 4
Concentration of stock solution (M): 1.94 x 10^-4 M (for all)
Volume of stock solution needed to prepare diluted standard solution (mL): (blank table)
Final Volume of standard solution (mL): 50.0 mL (for all)
Concentration of standard solution (M):
1: 3.87 x 10^-6 (M)
2: 9.70 x 10^-6 (M)
3: 2.91 x 10^-5 (M)
4: 3.87 x 10^-5 (M)

2) What range of wavelengths should be investigated with the spectrophotometer to determine the exact wavelength of maximum absorbance for the red dye? Use Table 2 on page 2, and report your answer using a complete sentence. (1 point)

3) What is molar absorptivity? How is it represented in the Beer-Lambert equation? What aspect of a standard curve reveals the molar absorptivity? (2 points)

4) Use the standard curve shown below (and the trendline equation included) to calculate the concentration of a sample that has a measured absorbance of 0.853 AU. What are the units for concentration in this specific example? (1 point)

Standard Curve for Green Dye (? = 642 nm)
y = 655.7x + 0.0129
R² = 0.99744
Concentration of Green Dye (g/mL)

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