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Part II

Chemistry

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Part II. Scoring Scheme: 3-3-2-1

Plot absorbance versus concentration in μmol/L of the Allura Red solution at the wavelength of the maximum absorbance of Allura Red, 480 nm, on a spreadsheet or a programmable calculator, and carefully determine the slope of the best straight line fit through the data.

 

Using this Beer's Law plot, you will determine the value of ε^*_AR480. The slope must be accurately determined because it will enable you to solve for the unknown concentrations of your mixture components.

 

CLICK HERE if you would like assistance using an Excel spreadsheet for determining the slope of a best fit line.      

 

Enter the value of your slope to 3 significant figures and in units of L/μmol.

 

Slope (L/μmol) = Your Answer: 0.0381You Scored 3 points out of 3 Possible  13)Part II. Data Entry. No Scoring.

Please enter the value of A⁴³⁰, the absorbance reading you measured for the mixture (i.e., unknown) at the wavelength of maximum absorbance of Tartrazine, 430 nm.

 

Report your value to 3 significant digits.

 

A⁴³⁰ =                                  Your Answer: 1.43  

 

14)Part II. Data Entry.

Please enter the value of A⁴⁸⁰, the absorbance reading you measured for the mixture (i.e., unknown) at the wavelength of maximum absorbance of Allura Red, 480 nm.

 

Report your value to 3 significant digits.

 

A⁴⁸⁰ =       Your Answer: 1.16No Points Possible 

 

Part II. Scoring Scheme: 3-3-2-1

Please enter the values you calculated for the concentrations of Tartrazine and Allura Red in the mixture.

 

(Use 3 significant figures.)TZ =AR =