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)

The absorbance of an unknown dye solution is measured to be 1.06 by a spectrometer. The calibration plot of the spectrometer is provided below. What is the molar concentration of the unknown sample (in mole L)? Absorbance vs. Molarity 18 y3 67024x-0.0343 16 14 12 1 0.8 0.6 0.4 0.2 01 0.2 0.000005 00001 0000015 Concentration of solutions, mol/L 0.00002 0.000025 000003 0 163e-5 O 2.35e-6 0 163 0 235 Absorbance

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] =

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)?

The spectroscopic data in the table is generated with five solutions of known concentration. Concentration (M) 0.0133 m= 0.0266 0.0532 0.106 0.213 Absorbance 0.1271 What is the intercept of the linear regression line? 0.08531 0.5388 1.069 Use a spreadsheet program, such as Microsoft Excel, to graph the data points and determine the equation of the best-fit line. 1.954 What is the slope of the linear regression line formed by these points? M-1