The concentrations of K* in water were measured with atomic absorption spectroscopy (AAS) and atomic emission spectroscopy (AES). Four water samples obtained at different cities were used, and each sample was measured one time. The measurements are shown in the table below: Tulare 8.9 ppm 7.0 ppm What is the calculated t-value (tcalculated) for the statistical comparison of these two methods? AAS AES 1.908 2.664 2.309 2.938 3.012 Fresno 5.5 ppm 5.4 ppm Clovis 6.7 ppm 5.0 ppm Selma 12.5 ppm 9.8 ppm

A 36.0 mg sample of an organic compound (molar mass = 84.0 g/mol) is dissolved in 10.0 mL of water. This aqueous solution is extracted with 5.0 mL of hexane. Separation and analysis of the aqueous phase shows that it now contains 12.0 mg of the organic compound. Calculate the partition coefficient for the compound between hexane and water (Kphexane/water). Your answer should reflect the proper number of significant figures.

(5) If 200 g of polymer A, 300 g of polymer B, 500 g polymer C, and 100 g of polymer D are mixed, calculate both M, and Mw of the blend? Polymer A Mn = 45,000; Polymer B M, = 100,000; Mw = 200,000 Polymer C M, = 80,000; Polymer D What are the polydispersity index and the standard deviation of the number distribution of molecular weight of the mixture? Mw = 65,000 Mw = 85,000 Mn = 300,000; Mw = 900,000

Use the data below from the titration of two water samples. Calculate the average ppm for the two trials. Volume of Water sample  used for each titration 50.31 Concentration of EDTA used for both trails 0.012 Trial 1                                                                       Trial 2 Initial Syringe Volume - 8.98                                    Initial Syringe Volume - 9.46 Final Syringe  Volume - 0.97                                    Final Syringe Volume  -  1.53

Bradford assay was used to determine bovine serum albumin (BSA) concentrations. The method works by binding Coomassie Brilliant Blue dye to protein standards and unknown, leading to a shift in the absorbance maximum of the dye. A stock solution of BSA is available (10 mg/ml) from which the protein standards were prepared. Bradford reagent, 290 ul, was pipetted into a transparent 96-well microplate. 10 ul of the protein dilution was added followed by mixing in the wells. After 5 min of incubation at room temperature, the plate was read in spectrum mode with the absorbance spectrometer of the microplate reader. The spectrum of the dye not bound to protein was also determined. Create a standard curve or regression equation that related the protein concentration and absorbance. An unknown BSA sample was prepared the same way as the standard and the OD was 0.35. determine the original concentration of the protein solution. The measurements can be seen below. 0.0625 Protein Concentration…

Determine the mean paracetamol content per tablet (in mg), using the following values: the mean absorbance 0.13, and molar absorption coefficient 9601.9 M−1 cm−1 , where the equivalent half of one tablet mass of powdered paracetamol tablets transferred is 296.4 mg and the mean paracetamol tablet weight is 599.1 mg. Give your answer to TWO decimal places (you do not need to include the units in your answer below).

I have set up my spreadsheet and was able to reproduce the result with a pKa of 4.64. TRUE OR FALSE

An atomic absorption method for the determination of the amount of iron present in used jet engine oil was found from pooling 30 triplicate analyses to have a standard deviation s = 3.1 µg Fe/mL. If s is a good estimate of o, calculate the 95 and 99% confidence intervals for the result 21.7 µg Fe/mL if it was based on the following criteria. (a) a single analysis 95% confidence interval= 21.7 + 99% confidence interval = 21.7 + (b) the mean of two analyses 95% confidence interval = 21.7 + 99% confidence interval= (c) the mean of six analyses 21.7 ± 95% confidence interval = 21.7 + 99% confidence interval= 21.7 + μg Fe/mL μg Fe/mL μg Fe/mL μg Fe/mL μg Fe/mL μg Fe/mL

Twenty dietary iron tablets with a total mass of 22.131 g were ground and mixed thoroughly. Then 2.998 g of the powder were dissolved in HNO3 and heated to convert all the iron to Fe31. Addition of NH3 precipitated Fe2O3 ? xH2O, which was ignited to give 0.264 g of Fe2O3 (FM 159.69). What is the average mass of FeSO4 ? 7H2O (FM 278.01) in each tablet?

A solution contains 0.10 M Sr(NO3)₂ and 0.20 M Bi(NO₂). When solid Na AsO is added to the solution a precipitate forms. What concentration of AsO ³ maintains maximum separation of Sr²+ and Bi³+? Ksp of Sr₂(AsO₂)₂ = 4.29 x 10-1⁹ and BIASO = 4.43 x 10-1⁰ 4 4/2