You obtained the following raw data when setting up a Bradford standard curve: BSA (mg/ml) Absorbancy 595nm 0 0.178 1 0.277 2 0.395 3 0.475 4 0.611 7 56989d 10 0.721 0.854 0.931 1.041 1.059 1.087 Set up a standard curve. What would the quality of the line-fit (R² value) be if you exclude experimental outliers? (Give you answer to 4 decimal places)

3. The lead in a swab sample, lead standards, together with a blank were made up in 5.00 mL volumetric flasks using 0.2 % HNO3. 20 μL aliquots of these solutions were injected into the spectrophotometer and the absorbance measured at 217 nm. The following results were obtained. lead / ppb Absorbance 0 0.0591 10.00 0.0858 50.00 0.1926 100.0 0.3260 150.0 0.4594 200.0 0.5929 Swab sample 0.3700 (a) Determine the amount of lead in the swab sample in μg.

3. Fill in the following for the correspondence between % transmittance and absorbance: 100.0 % T = 0.0 absorbance 1.00 absorbance = (0.0 % T 25.0 % T = absorbance 0.25 absorbance = % T

You measure a sample in your spectrophotometer that has an absorbance of 1.00. What is the concentration of your sample in M.

A student prepared four standard solutions of (NH4)2Fe(SO4)2 and measured their absorbance at 505 nm.  She created a calibration plot with the best-fit line of y = 9372 x + 0.0539.  She measured the absorbance of her diluted unknown sample solution as (4.69x10^-1) nm.  If she prepared her diluted sample solution by diluting 10.00 mL of the original solution to a total volume of 50.00 mL with deionized water, what is the concentration of Fe2+ in her original solution?  Answer in units of M. Note: Your answer is assumed to be reduced to the highest power possible.

After creating her standard curve for absorption versus the concentration (M) of FD&C Red 40, a student found that her best fit linear line for FD&C Red 40 was y = 2,681x + -0.002. Her Kool-Aid sample had an absorbance of 0.337. If 0.55 grams of Kool-Aid powder was used to prepare an 8-fl oz cup of her assigned flavor, what is the percent by mass of FD&C Red 40 in her 8-fl oz cup?

10 Wavelength, 1. (nm) E (Red, µ.Mcm- ɛ(Yellow, µMr'cm¬1) Absorbance 500 0.0369 0.000549 0.405 430 0.00506 0.0167 0.474 An orange colored solution is prepared by mixing a red dye solution with a yellow dye solution and the absorbance was measured at the analytical wavelengths of 430 nm and 500 nm. The table provides the molar absorptivity for the red and yellow dye at each analytical wavelength. Calculate the concentration (in u.M) of the red and yellow dye in the mixture. [red] = [yellow] =

A student generates a calibration curve of absorbance versus concentration of Red Dye #40. The equation of the line (with an R-squared of 0.9976) is y = 36385x + 3.724x10 -5. If they found the absorbance of their unknown dye solution to be 0.6585 AU; what is the concentration?

Quantitative Analysis by External Standard Method Calcium in a juice sample is determined by atomic absorption spectrophotometry. A stock solution of calcium is prepared by dissolving 1.834 g of CaCl, 2H20 in water and diluting to 1000.0 mL. A substock calcium solution was prepared by transferring 10.00 mL of the stock to a 100.00 mL volumetric flask and diluting to the mark. Three standard solutions of calcium were prepared by transferring 2.500 mL. 5.00 mL and 10.00 mL of substock to 50.00 mL volumetric flasks and diluting to the mark. The sample is prepared by transferring 1.000 mL of fruit juice from the original bottle to a 25.00 mL flask and diluting to the mark. Strontium chloride is added to all solutions before dilution to avoid phosphate interference. Instrumental response of the standards is measured against the blank, and the following readings are recorded: 9.10, 18.6 and 37.0. The sampie reading is 28.1. Using the multipoint method, find the concentration of calcium in…

2. ] You make 150.0 mL of a copper(II) sulfate solution but forget to cover it before leaving for the day. The next class, you measure the volume and find that you only have 132.0 mL remaining. You didn’t record the initial concentration, but you measure the absorbance of the remaining solution at 620 nm and find that it is 0.386. You also construct the following calibration curve for CuSO4: Standard solution Abs620 0.50 M 0.424 0.40 M 0.336 0.30 M 0.247 0.20 M 0.159 (refer to image) a. What is the value for k (in Beer’s Law)? Provide a calculation or graph to support your answer. b. What is the concentration of the (remaining) solution? c. What was the concentration of the original solution from the first class? d. If you removed 7.5 mL from the 132.0 mL solution in the process of measuring the absorbance, how much water should you add to obtain the original concentration that you solved for in part (c)?