Interpretation
Estimate the pK4 of the acid has to be calculated.
Concept introduction:
UV/vis spectroscopy: It is deal with information about various compounds that have conjugated double, the UV light and visible light have jest the right energy to cause an electronic transition in a molecule that is to promote an electron from one molecular orbital to another higher energy.
Henderson-Hesselbalch equation: The acid lose a proton in an aqueous solution depends on the both the
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Organic Chemistry
- 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.arrow_forward1.) Beer's Law can be used to find the concentration of a solution by measuring its absorbance. The law is given by ?=???A=ϵbC Where A is the absorbance, ?ϵ is the molar absorptivity, b is the pathlength of the light (the width of the sample cell), and C is the concentration of the solution. A student is analyzing a solution of a metal, and finds that the absorbance of the solution is 0.532. If ?=187 L⋅g−1⋅cm−1ϵ=187 L⋅g−1⋅cm−1 and ?=1 cmb=1 cm , what is the concentration of the metal in solution (in g/L)? * 352 * 2.84×10−32.84×10−3 * 2.84×10−22.84×10−2 * 96.8 2.) How many significant figures does the number 0.00358 have? Group of answer choices a.1 b.2 c.3 d.5 3.) A 10.00 mL solution of a certain food dye has a concentration of 1.47 g /L. What is the total mass of food dye in the solution? Report your answer with the correct number of significant figures.arrow_forwardThe molar absorptivity for the FD&C dye “Red No. 3” (Erythrosine) 8.25104 M‒1·cm‒1 at 526 nm. Calculate the expected absorbance of solution of Red No. 3 with a concentration of 4.00×10–6M when measured at 629 nm in a 2.00 cm cell.arrow_forward
- Absorbance at 453 nm 8393939 7 fl. oz./20 ml Beer-Lambert's Law (Spectrophotometry) #1 Fe (aq) + KSCN(s) FESCN "(aq) + K" (aq) 3+ To determine the moles of Fe (aq) in a 100. mL sample of an unknown solution, excess KSCN(s) is added to convert all the Fe (aq) into the dark red species FeSCN"(aq), as represented by the equation above. The absorbance of FESCN"(aq) at different concentrations is shown in the graph below. 2+ 0.50 目0.40 0.30 0.20 01 0. 0. 5 x 10-5 10 x 10-5 Concentration of FESCN2+ (M) If the absorbance of the mixture is 0.20 at 453 nm, haw many moles of Fe (aq) were present in the 100. mL sample? (Assume that any volume change due to adding the KSCN(s) Iis negligible.) 3+, 4x10-4 mol 3 x 104 mol (B) 4x 10-6 mol 3x 10-6 molarrow_forwardWhat is the absorbance of a 2.33×10−4M2.33×10−4M solution of a compound with a molar absorptivity of 1.05×103M−1cm−11.05×103M−1cm−1 in a 1.00 cm cell?arrow_forwardThe standard curve was made by spectrophotographic analysis of equilibrated iron(III) thiocyanate solutions of known concentration. You are asked to analyze a Fe(SCN)2+ solution with an unknown concentration and an absorbance value of 0.392. The slope-intercept form of the equation of the line is y = 4538.1x +0.0077. The unknown was analyzed on the same instrument as the standard curve solutions at the same temperature. What is the Fe³+ concentration of the unknown solution? [Fe³+] = mol/L Absorbance Iron(III) thiocynate standard curve 1.0 V 0.5 0.0001 Fe³+ concentration (M) 0 0.0002arrow_forward
- The intensity of red light (680 nm) and sorted by a solution of green dye was found to be 1.99 V and the intensity of light when no dye was present (the blank) was found to be 2.69 V.What is the absorbable of the solution of green dye in three significant figuresarrow_forwardIn an analytical laboratory a chemical compound namely Paracetamol (151.163 g/mol) is determined in a sample. A sample weighing 0.0295 g was dissolved in a solvent and diluted the solution to 1 L. The solution has λ max at 243 nm (ε=2.6×104 cm-1 mol-1 L). The solution exhibits an absorbance of 0.638 in a 2 cm cell. Calculate the percentage paracetamol in the sample.arrow_forwardThe absorbance of an unknown dye solution is measured to be 0.47 by a spectrometer. The linear equation of the spectrometer's calibration plot is y= 2156.5 x +0.0213, where y represents absorbance and x represents concentrations of dye. What is the molar concentration of the unknown sample (in mole L)? O2.08e4 O 2.08e-4 0 125e3 0 125e-3arrow_forward
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