Question

Question 1 5 pts The extinction coefficient for FD&C Blue Dye #1 is 138,500 cm-L/mol at 630 nm. A chemist collected the following data at 630 nm. She also found that the absorbance of an FD&C Blue Dye #1 solution of unknown concentration was 0.212. Use your graphing calculator to generate a standard curve from this data set, and use it to determine the concentration of the unknown solution. Express your answer in 10-SM (if your answer is 5.52x10-SM then just enter 5.52 as your answer) Concentration Absorbance of Blue Dye (M) @ 630 nm 7.58x10-6 0.101 3.26x105 0.288 5.17X105 0.521 8.63x105 0.782 Question 2 5 pts The extinction coefficient for FD&C Blue Dye #1 is 138,500 cm-L/mol at 630 nm and has a molar mass of 792.844g/mol. A chemist collected the following data at 630 nm. Concentration Absorbance of Blue Dye (M) @ 630 nm 7.58x106 0.101 3.26x105 0.288 5.17x10-5 0.521 8.63x105 0.782 A chemist prepared a Koolaid grape flavor sample by weighing out 0.088g of Koolaid grape and dissolving it in a 100mL volumetric flask. She also found that the absorbance at 630nm of her Koolaid grape solution of unknown concentration of blue dye was 0.519. Determine the mass % of blue dye in Koolaid grape.

Answer 1

0.9 0.8 y=8840.4x + 0.0292 0.7 0.6 0.5 Absorbance 0.4 0.3 0.2 0.1 0 0 0.00002 0.00008 0.0001 0.00004 0.00006 Concentration

1. Answers from graph : y =8840.44 2 70.0992 -0 y-ani's absorbance (A) x-axis concentration (C) → A 884014ct 0.00292 kg Absorbance of unknown = A = 0.dld = 0.412 = 884014C+ 0·0292 2.07x10-5 M c = '. Concentration of unknown = 9.078105 an

2. Answers En 2 Is A-888004 C+0.0 292 Absol bance of unknown = o.sla 70-519 - 8840.4 C+0.0292 c = 5.59x10-5 м. 5054X10sxool Volume of soletion - 100ML = O:) moles of FDRC Blue dye = 5054 X106 moles moleu mass of FD & C Blue of FD & C Blue Boge = 792. 86 =992. 8cre glmol Amount of FD&C Blue dye in Sample -6 5159x10x792.849 -0.00439 g mass of Kooloid Saniple sesed. %FD&C Blue dye 0.088 88 g 0.00439 00088 XIOO =4.99% o