College Chemistry Lab
posted by L** .
Suppose that a 2.50x10^6M solution of red dye No. 2 had an absorbance of 0.585 at its wavelength of maximum absorbance. A second solution of red dye No. 2 is too concentrated to read its absorbance so 5.00 mL of the concentrated dye solution was diluted with water to a volume of 150 mL. The diluted solution has an absorbance of 0.289, measured under identical conditions. What is the molarity of dye in the concentrated solution?

For the first one,
Absorbance = kc
A = 0.585, solve for k, c = 2.50 x 10^6M
Use k in the second run of the concd stuff.
A = kc
You will get a concn that must be adjusted because of the dilution. How much was it diluted. From 5 to 150 mL; therefore, the concn will whatever you calculate x the factor 150/5.
Or you can look at it another way. You can say that the absorbance would have been higher than 0.289 by 0.289 x (150/5), then work A = kc the normal way.
Respond to this Question
Similar Questions

Chemistry
Why are different wavelengths used for red and blue dye in a spectrophotometer? 
College Chemistry Lab
The absorbance of a 6.3x10^5M solution of an iron complex was measured to be 0.328 at the optimum wavelength. A second solution of the iron complex has an absorbance of 0.833 measured under identical conditions. What is the molarity … 
College Chemistry Lab
The absorbance of a 9.25x10^8M solution of a fabric dye was measured to be 0.835 at a particular wavelength. What would the absorbance be for a 4.65x10^8M solution of the same dye under identical conditions? 
rate laws and concentrations :: Chemistry.
A student studied the kinetics of the reaction of sodium hypochlorite and a vegetable dye by the method of pseudo order. He mixed 5 mL of a 0.67 M solution of NaOCl with 15 mL of a vegetable dye, he took a portion of the mixture and … 
Chem
I have no idea What to do. What does it mean by 'draw what you think the visible range spectrum of this dye would look like.' To get the A, I used Beer's law. So I got 9.265nm for Absorbance. What should I do for the next? 
chemistry
for our lab, we are given the molarity of ClO. We are then supposed to use beer's law to determine the molarity of the dye that was used to make the solution with. For the dye, use the first absorbance value, Ao, and calculate the … 
Chemistry
A student measures k for a certain blue dye to be 19.4 M^1 at 560 nm. What is the molarity of the dye in a solution with an absorbance of 0.118 at this wavelength? 
Biochemistry
Can someone help me calculate protein concentration using the Bradford Assay? 
Chemistry
A student measures k for a certain blue due to be 19.4 m^1 at 560 nm. What is the molarity of the dye in a solution with an absorbance of .118 at this wavelength ? 
Chemistry
A dye has a λmax = 460 nm (ε = 70,000 L/(mol*cm)). What is the concentration of dye in a sample whose absorbance at 460 nm is A = 0.350 in a cell with a path length of 1.00 cm (4 points) I have no idea how to do this.