Food Dyes Analysis of Commercial Products Part 2 (1)

At what wavelength was Pb determined? What is the slope and  y-intercept of the calibration curve? The researcher determined the Pb content of water sample from a river suspected to be contaminated with Pb from a nearby factory by complexing with cyanidine and the absorbance measured was 0.405. What is the lead content of the water sample?

5 What is the atomic number of a neutral atom that has 8 neutrons and 7 electrons? a.    15b.    8c.    7d.    1 6 Methods that employ separation of the product chemically through precipitation, with purification, drying and weighing of the resultant product: A.    Spectrophotometric analysisB.    Volumetric analysisC.    Gravimetric analysisD.    Gasometric analysis7 Phase changes involving fusion, except:a.    Solid to liquidb.    Liquid to solidc.    Gas to liquidd.    Gas to solid

Determine the final concentration in mol dm–3 of K+ and SO42– when the following three solutions in volumetric flasks are mixed together: 500 cm3 of 0.20 mol dm–3 KAl(SO4) 2; 1000 cm3 of 0.050 mol dm–3 K2SO4 and 500 cm3 of water. The concentration of K+ is       Select one: a. 0.20 × 103 mol dm–3 b. 0.20 mol dm–3 c. 0.10 × 10–3 mol dm–3 d. 0.10 mol dm–3

Using the data and formula given below, compute for the potency of Lot No. 3006, 2901 & 2892:

Explain the assumptions of steady-state approximation.

Please explain the answer. Plotting the ratio of atomic emission of Pb to the atomic emission of yttrium (internal standard) vs the concentration of Pb in contaminated water, the linear regression equation from 10-point calibration was found to be y=0.114x-1.8872. What would be the average concentration of Pb in contaminated water if three aliquot of a sample of 10 folds' diluted solution of contaminated water provided the ratio of emission of Pb to that of yttrium as: 3.92, 3.86, and 3.87? а. 3.89 ppb b. 38.9 ppb с. 357 ppb d. 35.7 ppb

In order to measure riboflavin in a breakfast cereal, a 5.00-gram sample of the cereal was extracted with acetic acid and filtered. The extract was transferred to a 50.0 mL volumetric flask and diluted to the mark. The sample was transferred to a cuvette and the fluorescence was measured. The instrument read 59 units (Fluorescence units –an arbitrary scale). 24.00 mL of the cereal extract was sample was mixed with 1.0 mL of a riboflavin standard that was 0.500 ug/mL. The fluorescence of this mixture was measured and read 94 fluorescence units. Calculate the concentration of riboflavin per gram of cereal (use µg/gram of cereal).

5

Quinine in a 1.553-g antimalarial tablet was dissolved in sufficient 0.10 M HCl to give 250 mL of solution.A 10.00-mL aliquot was then diluted to 50.00 mL with the acid. The fluorescence intensity for the dilutedsample at 347.5 nm provided a reading of 196 on an arbitrary scale. A standard 100-ppm quinine solutionregistered 125 when measured under conditions identical to those for the diluted sample. Calculate the massin milligrams of quinine in the tablet.

Write the Lineweaver–Burk (doublereciprocal) equation and describe thefeatures of a Lineweaver–Burk plot.

Suppose the difference in rest energy of the neutron and proton were Qn = (mn − mp)c2 = x MeV instead of Qn = 1.29MeV, with all other physical parameters unchanged. Estimate Ymax, the maximum possible mass fraction in 4He, assuming that all available neutrons are incorporated into 4He nuclei. Hint: Compare the new rest energy of the neutron to the electron and consider how that would impact the decay of neutrons.  Will free neutrons decay at all in this scenario?  If the neutron decay is negligible, then the ratio of protons to neutrons to protons will remain the same as it was at the time of freeze-out (for a given Qn).   Value: x=0.158 MeV

Calculate the molar extinction coefficient (e) of a molecule at a particular wavelength given that a 0.000764 M solution of the molecule produced a fluorescence intensity (I) of 1177 when the irradiance of the beam incident to the sample (Po) was 821 and the length of the medium (b) was 1.12 cm. The proportionality constant k' for this molecule is 0.319. € = ×10 TOOLS M-1.cm-1

For a molecule, the phosphorescence lifetime without quenching is 1.0 s while with a quencher population of 10-2 M the phosphorescence lifetime is 0.10 s. Calculate the rate constant for phosphorescence assuming that kisc >> (kF + kec + kic). Calculate the rate constant for external conversion of the triplet state (kec’), the quenching rate constant for the triplet state (kq’), and the Stern-Volmer quenching constant. Assume that intersystem crossing from T1 to So is negligible.

Derive step by step. (2nd order conc-time eq)  dCA/dt = kCA2

A 25.0 mL aliquot was taken from a 500.0 mL sample of tonic water containing an unknown amount of quinine and diluted to a volume of 200 mL. At 347.5 nm, the fluorescence intensity of the diluted sample was measured 85.7 an arbitrary scale. Under similar conditions, a 27.5 ppm standard quinine solution had a fluorescence intensity of 185. Calculate the mass of quinine in the original tonic water sample in mg.  Do not include units in your answer.

to Johnston Commun X Rh Blackboard Collaborate Ultra - x > General Psychology-Fall 2021 A ALEKS - Griffin Barden - Learn + A www-awa.aleks.com/alekscgi/x/Isl.exe/1o_u-IgNslkr7j8P3jH-IJczzdcvSCzsqTCIDqNGV3bKqhMfPmUcQ4ENkmiXn9QCwgeDPDkQ06yszYWESPcekwLO-Qg619rekU7404HgFAGbEZa Dr080?1 oBw7QYjlbavbSPXtx-YCjsh_7mMmrq#item O THERMOCHEMISTRY Griffin Calculating a molar heat of reaction from formation enthalpies Using the table of standard formation enthalpies that you'll find under the ALEKS Data tab, calculate the reaction enthalpy of this reaction under standard conditions: 2C,H;(g)+70,(9)→4 CO,(g)+6H,O() Round your answer to the nearest kJ.

Discuss qualitatively how you would expect the exciton binding energy in a GaAs/Alo.3Gao.7As quantum well to vary with the quantum well thickness, given that the binding energy of the excitons in bulk GaAs and Alo.3Gao.7As are 4 meV and 6 meV respectively.

In a photochemical experiment it is observed that 5.78×10-5 mol of uranyl oxalate is decomposed at a wavelength of 300 nm emitted by a lamp in one hour. When acetone was irradiated with the same lamp for 10 hours, the amount of acetone decomposed was found to be 2.32× 10-4 mol. What is quantumyield for the acetone decomposition under the same condition?

The space immediately surrounding stars, the circumstellar space, is significantly warmer because stars are very intense black-body emitters with temperatures of several thousand kelvin. Discuss how such factors as cloud temperature, particle density, and particle velocity may affect the rotational spectrum of CO in an interstellar cloud. What new features in the spectrum of CO can be observed in gas ejected from and still near a star with temperatures of about 1000 K, relative to gas in a cloud with temperature of about 10 K? Explain how these features may be used to distinguish between circumstellar and interstellar material on the basis of the rotational spectrum of CO.

Consider the quenching of an organic fluorescent species with τ0 = 6.0 ns by a d-metal ion with kQ = 3.0 × 108 dm3 mol−1 s−1. Predict the concentration of quencher required to decrease the fluorescence intensity of the organic species to 50 per cent of the unquenched value.

Please don't provide handwritten solution ....

The data given below was generated by a student in Bio 240L during a Bradford Assay. A standard curve was generated by preparing a set of standard samples of protein (bovine serum albumin) and adding the dye Coomassie Brilliant Blue, When the protein binds to Coomassie Brilliant Blue it absorbed light at 595 nm with an extinction coefficient of 43,000 M-1 cm-1. After the dye binding reaction was complete, absorbance values for each protein standard solution were measured at 595 nm and recorded. Standard # 1 2 13 4 Concentration of protein binded to Coomassie Brilliant Blue (M) 6.35x10-7 1.23x10-6 3.85x10-6 5.68x10-6 OOO Absorbance at 595 nm 0.093 0.176 0.560 0.813 Prepare a standard curve with the student generated data. What is the slope from the standard curve rounded to four sig figs and no units? 1.4 143398 6.972x10-6 1.434x105

17. Advection is represented in the advection-dispersion equation by the term +v Əc/ax +KC -v ac/ax -μС

DELFIA® (Dissociation Enhanced Lanthanoid Fluorescence Immunoassay) is a time resolved fluorescence (TRF) assay. Based on the attached figure, the time in us in which the fluorescent signal of the analyte should be read is: Laser pulse 200 400 600 800 1 000 Time (us) Select one: О а. 500 O b. 150 О с. 100 O d. 50 O e. 25 Fluorescence intensity -------

When opening the cover of an analytical detector, which optical elements can help us to differentiate whether the instrument is a spectrofluorometer or a UV-Vis spectrophotometer. Justify your answer:

PLEASE ANSWER!!!!

What is the actual or real-life application of electrogravimetric analysis? Include the specific methodology.

(c) Comment on the truth, or otherwise, of the following statement. "Fast time-scale flash photolysis can be used to determine rate constants for collisional relaxation (quenching) processes of singlet and triplet states. Radiative decay rate constants (Einstein A coefficients) can be determined from such measurements, and can also be calculated from absorption coefficients."