Determine the molar absorbtivity of the acidic form of bromocresol green at 445 nm and at...
Determine the molar absorbtivity of the acidic form of bromocresol green at 445 nm and at 615 nm of a solution that contains 40 mL of 0.4M HCl and 10 mL bromocresol green. The stock solution of bromocresol green is 80 mg/L and the molar mass is 698.0 g/mol. At 445 nm the absorbance reads 0.430 and at 615 nm the absorbance reads 0.007.
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Determine the molar absorbtivity of the acidic form of
bromocresol green at 445 nm and at...
You prepared four standard solutions by serial dilutions that contained decreasing concentrations of bromocresol green, but...
You prepared four standard solutions by serial dilutions that contained decreasing concentrations of bromocresol green, but constant HCl concentration. You also prepared four additional standard solutions by serial dilutions that contained decreasing concentrations of bromocresol green, but constant NaOH concentration. You then measured the absorbances of these solutions at their respective lamba max wavelengths (AX1 & A2). These absorbances were plotted versus Hin and In molar concentrations respecti vely to produce linear calibration curves with linear equations shown below. AX1...
A calibration curve was prepared to determine the concentration of albumin (MW 66500 g/mol) in a...
A calibration curve was prepared to determine the concentration of albumin (MW 66500 g/mol) in a human serum sample. The serum sample was prepared by mixing it with a prepared bromocrestol green indicator buffer. Bromocrestol green creates a complex with albumin, which results in a colour change at 615 nm. Calibration standards were prepared by dissolving 133, 200, 266, 333 and 400 mg of albumin in 10.00 mL of the bromocrestol green buffer solution. The absorbances of the standards were...
need help on these Suppose you obtained the following data from two standard solutions of known...
need help on these
Suppose you obtained the following data from two standard solutions of known concentrations using a UV-Vis spectroscope: Analysis # Conc. (mg/L) 8.00 20.00 Absorbance (at 255 nm) 0.160 0.390 What is the concentration (in mg/L) of an unknown solution with an absorbance of 0.200 at 255 nm 10 points)? The unknown solution contains the same analyte as the standard solution does (Assume a path length of 1cm). 10. You prepared a stock solution by dissolving a...
Given the fact that the molar extinction coefficient at 470 nm is 6800 cm-1 M-1 and...
Given the fact that the molar extinction coefficient at 470 nm is 6800 cm-1 M-1 and the radius of the 4-dram vial is 1.00 cm, what would be the absorbance for the highest standard solution (25.00 mL) and for the lowest standard (5.00 mL)? Preparation of iron standard solution (0.01 mg/mL): Weigh (to the nearest 0.1 mg) 0.0350 g of reagent grade (NH4)2Fe(SO4)2•6 H2O into a 500-mL volumetric flask. Dissolve in 250 mL of water that contains ~1 mL of...
Hi, I need help with answering these questions. Thank you. 1) What is the molar absorptivity...
Hi, I need help with answering these questions. Thank you.
1) What is the molar absorptivity of riboflavin (with units)?
Assume that the cuvette has a pathlength of 1.00 cm and that the
blank had an absorbance of 0.00.
2. If a sample of riboflavin with an unknown concentration had
an absorbance of 0.597, what is the concentration of the
sample?
3. A sample of riboflavin is prepared by crushing 5 tablets and
dissolving them in enough water to create...
4. (a) Determine the experimental concentration of protein in the unknown solution in mg/mL using the...
4. (a) Determine the experimental concentration of protein in the unknown solution in mg/mL using the Part II Data Table and the equation on page 2 for the absorbance assay at 280 nm. Hint: Convert the molar concentration (M or moles/liter) of BSA from absorbance assay at 280 nm method to mg/mL, assume that the molecular weight of BSA = 66.5 kDa [7 points 6500 g/mol Post-lab 10 Report Form: Determination the Concentration of a Protein You must show your...
Question 2 Compound "Y" (molar mass = 480.5 g moll) used as a food coloring. Following...
Question 2 Compound "Y" (molar mass = 480.5 g moll) used as a food coloring. Following experiment was carried out to find the concentration of "Y" in a beverage. A stock solution of compound "Y" (concentration = 7.50 0 10-4 mol L-) was used to prepare a series of standard solutions. Calibrated pipets and 100.0 mL volumetric flasks were used for these preparations. Then, absorbance of these solutions were measured at 460 nm using 1-cm cuvettes. A dilution was carried...
The molar absorptivity constant for the allergy drug Zyrtec (cetirizine) (MW 388.89 g/mol) is 7,250 L/mol*cm...
The molar absorptivity constant for the allergy drug Zyrtec (cetirizine) (MW 388.89 g/mol) is 7,250 L/mol*cm at 245nm. Given a stock solution with a cetirizine concentration of 0.537 mg/mL, specifically describe the best way to prepare a standard solution that would give you an absorbance of about 0.6 @ 245nm? What is the cetirizine concentration of that standard solution? 2) Describe exactly (show calculations) how you will prepare a 0.010 M Fell working stock solution from a stock solution that...
Suppose you are performing a gas-producing reaction to experimentally determine the molar volume of the gas...
Suppose you are performing a gas-producing reaction to experimentally determine the molar volume of the gas at STP. Mg(s) + 2 HCl(aq) + MgCl2 (aq) + H2(g) A sample of 0.0883 g of Mg, which has a molar mass of 24.31 g/mol, produces 82.5 mL of H2 gas. The gas is collected over water at an atmospheric pressure of 774.5 mm Hg at 22 °C, at which the vapor pressure of water is 19.8 mm Hg. What is the experimental...
Red food dye (FD&C Red 40, also known as allura red AC) has the formula C18H14N2Na2O8S2....
Red food dye (FD&C Red 40, also known as allura red AC) has the formula C18H14N2Na2O8S2. 1. What is the molar mass of FD&C Red 40? To make a solution you take 0.0097 g of FD&C Red 40. 2. How many moles of FD&C Red 40 are in your sample? You dissolve the sample of FD&C Red 40 in enough water to make 250.0 mL of solution. We call this the stock solution. 3. What is the concentration of the...
You prepared four standard solutions by serial dilutions that contained decreasing concentrations of bromocresol green, but constant HCl concentration. You also prepared four additional standard solutions by serial dilutions that contained decreasing concentrations of bromocresol green, but constant NaOH concentration. You then measured the absorbances of these solutions at their respective lamba max wavelengths (AX1 & A2). These absorbances were plotted versus Hin and In molar concentrations respecti vely to produce linear calibration curves with linear equations shown below. AX1...
A calibration curve was prepared to determine the concentration of albumin (MW 66500 g/mol) in a human serum sample. The serum sample was prepared by mixing it with a prepared bromocrestol green indicator buffer. Bromocrestol green creates a complex with albumin, which results in a colour change at 615 nm. Calibration standards were prepared by dissolving 133, 200, 266, 333 and 400 mg of albumin in 10.00 mL of the bromocrestol green buffer solution. The absorbances of the standards were...
need help on these
Suppose you obtained the following data from two standard solutions of known concentrations using a UV-Vis spectroscope: Analysis # Conc. (mg/L) 8.00 20.00 Absorbance (at 255 nm) 0.160 0.390 What is the concentration (in mg/L) of an unknown solution with an absorbance of 0.200 at 255 nm 10 points)? The unknown solution contains the same analyte as the standard solution does (Assume a path length of 1cm). 10. You prepared a stock solution by dissolving a...
Hi, I need help with answering these questions. Thank you.
1) What is the molar absorptivity of riboflavin (with units)?
Assume that the cuvette has a pathlength of 1.00 cm and that the
blank had an absorbance of 0.00.
2. If a sample of riboflavin with an unknown concentration had
an absorbance of 0.597, what is the concentration of the
sample?
3. A sample of riboflavin is prepared by crushing 5 tablets and
dissolving them in enough water to create...
4. (a) Determine the experimental concentration of protein in the unknown solution in mg/mL using the Part II Data Table and the equation on page 2 for the absorbance assay at 280 nm. Hint: Convert the molar concentration (M or moles/liter) of BSA from absorbance assay at 280 nm method to mg/mL, assume that the molecular weight of BSA = 66.5 kDa [7 points 6500 g/mol Post-lab 10 Report Form: Determination the Concentration of a Protein You must show your...
Question 2 Compound "Y" (molar mass = 480.5 g moll) used as a food coloring. Following experiment was carried out to find the concentration of "Y" in a beverage. A stock solution of compound "Y" (concentration = 7.50 0 10-4 mol L-) was used to prepare a series of standard solutions. Calibrated pipets and 100.0 mL volumetric flasks were used for these preparations. Then, absorbance of these solutions were measured at 460 nm using 1-cm cuvettes. A dilution was carried...
The molar absorptivity constant for the allergy drug Zyrtec (cetirizine) (MW 388.89 g/mol) is 7,250 L/mol*cm at 245nm. Given a stock solution with a cetirizine concentration of 0.537 mg/mL, specifically describe the best way to prepare a standard solution that would give you an absorbance of about 0.6 @ 245nm? What is the cetirizine concentration of that standard solution? 2) Describe exactly (show calculations) how you will prepare a 0.010 M Fell working stock solution from a stock solution that...
Suppose you are performing a gas-producing reaction to experimentally determine the molar volume of the gas at STP. Mg(s) + 2 HCl(aq) + MgCl2 (aq) + H2(g) A sample of 0.0883 g of Mg, which has a molar mass of 24.31 g/mol, produces 82.5 mL of H2 gas. The gas is collected over water at an atmospheric pressure of 774.5 mm Hg at 22 °C, at which the vapor pressure of water is 19.8 mm Hg. What is the experimental...
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