Question

4. The total absorbance of a solution is the sum of the absorbances of all different materials present. At = A + Ab + Ac ... etc. At 427 nm, the molar absorbtivity of Yellow #5 is 2.73x10^M-.cm . At 427 nm the molar absorptivity of Red 40 is 7.49x109 M.cm? Calculate the total absorbance of a solution in which the concentration of Yellow #5 = 4.00x10' M and the concentration of Red 40 - 2.80x10-5M, when measured at 427 nm in a 1.00 cin celish CamScanner

Answer 1

Answer of Question No.5: Total absorbance of a solution is the sum of the absorbance of au citrerent material present in the soulim In the given problem, two ditterent material present in a solution One 13 Yellow #5 M 8 another i3 Red 40(R) We have to caculate the total absorbace or the solutim - Total absorbance. At = Ay + AR] - Ay = Absorbance of Yellow #5 solution : AR Absorbance of Red 40 solution • a Beer-Lambert law : A= E.C.e. A = Absorbance of the solution E = Molar. absorbtivity of the solution C = Molar concentration of the solution: 1- Thickness of the cell. a Given Data Thickness of the cell (U) = 1.00 cm At 427 nm, fy = 2.73X104 u em ER = 7:49 x103 mt umt. Cy = 4.00x10-5 m CR = 2-80X1005 y & Cy are Molar absorbtivity & concentralfion of Yellow # 5 solution respechively

ER O CR are the Motar absorbtivity and concen tration of Red 40 solution : Now, Absorbance of Yellow #5 sowtion > Ay = {y cyl = (2.73X109) intom" x 14.00 x10-2m xrou) cm Ay = 1.092] Absorbance of Red 40 solution → AR = ER CR l = (7-49x103)mom(280810-53m x(1.689 cm TAR = 0.209 - Now, Total Absorbance , At = AXTAR :. Ap=1.092 + 0.209 A = 1.301 Ans. Total absorbance at the solulton measured at 427 nm in a 100 cm cell is = 1301 -