Question

2. A yellow dye, FD&C yellow 3, is used in some candy coatings. A 1.50 X 10M solution of this dye has an absorbance of 0.209 at its a. Calculate the molar absorptivity, €, of the dye at this wavelength, assuming a sample cell with a 1.0 cm pathlength. b. The yellow dye from one piece of candy is completely extracted into 10.0 mL of water and diluted to 50.0 mL with water. The absorbance of the diluted solution is 0.496 at its 2 Calculate the molarity of the dye in the diluted solution c. Calculate the number of grams of this dye in the coating of one piece of candy (MM of dye = 271 g/mol). 89

Answer 1

) COV 8. Sof" from Beer lambaet's law, We know that of hinde А &cx A absorbance & molar absorptinity et de concentration. & path length (a) Its given that a solution of c= 1.50x 10 7 A = 0.209 8 = 1.0cm. amoiolon cl. = 0. 209 1.50 x 105 MX 1.0cm.. = 0.209. 105x105 cm = 0. 1. 3 933x 105 mol L cm! - 139333molº2 em [M- mole'].

① given that A =.0.496 ΑεεΑ. Cuising from @) A E& R 0.496/13933.3 x 1 cm I mot Lomt

up C 50.000 0355 moll? Now Its said that it has been extracted inte 10.0 ml of water and diluted to some waler MIVI = M₂ V 2.0 o/ LY = 0.0000 355 mol L' x 10 ml = M X 50.0 ml. > M2 = 60° 0.0000355.x 10 wad 150 nel E 0.000000 7 1 mol L ' ③ maddimotes of edges 2 Ploe/rest. - molecular mass of dye = 271 g/mol. .. no. of moles = 0.0000071 {in 50 ml sol no. of moles= mass molecular weight → mass = 0.00000071x 291 -in. 0 0 0 1 9 241 g = 0.192 ma
part 3