Chapter 2, Problem 11P

Q3)a) Discuss the any two applications of Beer’s law with suitable justification. (b) In 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. (c) Analyze any two causes of non-linearity of curve in the Beer’s law.

To determine the molar concentration of a metal ion in a solution of unknown concentration, a student fırst made five standard solutions that contain the metal ion of interest and measured the absorbance of each solution in a spectrophotometer at its Amax- A calibration curve was obtained that had an equation of y = 5.747 x + 0.013 Next, the student pipetted 15.0 mL of the initial solution of unknown concentration into a 100.0 mL volumetric flask, and filled the flask with deionized water to the line. The absorbance of this final diluted solution was found to be A = 0.226 at Amax. The color of the original and diluted solution was blue. What is the molarity of the original solution, as well as an approximate Amax for this metal ion? 2max = 599 nm and concentration is 0.247 M Amax 457 nm and concentration is 0.247 M %3D 2 max = 457 nm and concentration is 0.0371 M 1 max 599 nm and concentration is 0.0371 M Amax = 599 nm and concentration is 0.00557 M

In a survey of 1000 large corporations, 250 said that, given a choice between a job candidate who smokes and an equally qualified nonsmoker, the nonsmoker would get the job (USA Today).(a) Let p represent the proportion of all corporations preferring a nonsmoking candidate. Find a point estimate for p.(b) Find a 0.95 confidence interval for p.(c) As a news writer, how would you report the survey results regarding the proportion of corporations that hire the equally qualified nonsmoker? What is the margin of error based on a 95% confidence interval?

1 A volumetric iron analysis on triplicate samples of the blood serum of a patient believed to be suffering from anaemia condition produced the following data: 3.15, 3.25, 3.26 mmol Fe/L. What is the 95% confidence interval for the mean data, assuming: a) No prior information about the precision of the analysis? b) S>0 = 0.056 mmol Fe/L?

You are preparing a 100.0 mL standard solution needed for titration analysis. The NaOH (40 g/mol) pellets are measured to be 0.5341 g in a balance with acceptable uncertainty of +0.001 g. Mass of the pellets is recorded after taring the container. The pellets are put in a beaker and added with 50 ml distilled water measured by a graduated cylinder. The solution is then quantitatively transferred to a 100-mL volumetric flask with uncertainty of ±0.08 mL and diluted to a 100-mL mark. What is the concentration (M) of the solution and estimate its uncertainty by propagation? Assumption: There is no uncertainty in molar mass. Express your answer as C+/- u M.

A new procedure for the rapid determination of sulphur in kerosene was tested on a sample known from its method of preparation to contain 0.123% S (µ = 0.123% S). The results for % S were 0.112, 0.118, 0.115, and 0.119. Determine whether the data indicate that there is a bias in the method at the 95% confidence level

(a) Standard Ag1 solution was prepared by dissolving 1.224 3 g of dry AgNO3 (FM 169.87) in water in a 500.0-mL volumetric flask. A dilution was made by delivering 25.00 mL of solution with a pipet to a second 500.0-mL volumetric flask and diluting to the mark. Find the concentration of Ag1 in the dilute solution. (b) A 25.00-mL aliquot of unknown containing Cl2 was titrated with the dilute Ag1 solution, and the equivalence point was reached when 37.38 mL of Ag1 solution had been delivered. Find the concentration of Cl2 in the unknown.

In the Analytical Chemistry laboratory, one of the B.Sc student Ms. Fatma wanted to analyze the presence of Iron(II) ion in the water samples collected from Sohar Industrial Area in the Sultanate of Oman and analyzed by Spectrophotometric method. (1) 250.00 mL of this water sample (Solution A) known to contain unknown amount of FeSO4. She has diluted Solution A by a dilution factor 10 to make 250.00 mL solution, which she labeled Solution B. Using Spectrophotometer, she has measured the absorbance value (0.642) for Solution B at 508 nm using 1.00 cm cell (cuvet). The molar absorptivity value for Fe2* ion at 508 nm is ɛ508 = 30.8 M-1cm1. (i) What volume of the solution A did she require to make the 250.00 mL of Solution В? (ii) in (i)? What instrument should she use to transfer the volume of the Solution A calculated (ii) Concentration of FeSO4 in Solution B. (iv) Concentration of FeSO4 in Solution A. Mass of FeSO4 in Solution A (Show your calculation) (v)

Sodium carbonate is a reagent that may be used to standardize acids in the same way that you have used KHP in this experiment. In such a standardization it was found that a 0.498-g sample of sodium carbonate required   24.8 mLmL   mL of a sulfuric acid solution to reach the end point for the reaction.  Na2CO3(aq)+H2SO4(aq)→H2O(l)+CO2(g)+Na2SO4(aq)Na2CO3(aq)+H2SO4(aq)→H2O(l)+CO2(g)+Na2SO4(aq)  What is the molarity of the H2SO4H2SO4?