Concept explainers
Interpretation:
The calibration curve between absorbance and concentration of standard series should be plotted. Using the regression line & the plot the concentration of the unknown solution should be calculated. The accuracy of these 2 methods should be compared by considering the final answers.Error analysis of the data should be done.
Concept introduction:
The absorbance of light can be determined by the Beer-Lambert law. The chemical equation relevant to the law is,
Where,
Standard deviation of a data series can be calculated by the following equation.
Trending nowThis is a popular solution!
Chapter 13 Solutions
Principles of Instrumental Analysis
- Mass spectrometry is an extremely versatile detection system for GC. However, interfacing an HPLC system to a mass spectrometer is a much more difficult task. Describe the major reasons why it is more difficult to combine HPLC with mass spectrometry than it is to combine GC with mass spectrometry.arrow_forwardA compound X is to be determined by UV/Visible spectrophotometry. A calibration curve is constructed from standard solutions of X with the following results: 0.50 ppm, A =0.24; 1.5 ppm, A =0.36; 2.5 ppm, A = 0.44; 3.5 ppm, A = 0.59; 4.5 ppm, A =0.70. Find the slope and intercept of the calibration curve, the standard error in y, the concentration of the solution of unknown X concentration and the standard deviation in the concentration of X. Construct a plot of the calibration curve and determine the unknown concentration by hand from the plot (only for the calibration curve, slope and y-intercept. Make an equation on how to solve for the concentration of unknown).arrow_forwardThe following data are obtained from three standard soltions using UV-Vis spectroscopy: What is the colar concentration (M) of an unknown solution with an absorbance of 0.180 at 255 nm? The unknown solution contains the same analyte as the standard solution does. The molar mass of the analyte is 188.65 g/mol a) 4.82x10-5b)1.9x10-3c)3.60x10-4d)1.9x10-5e)1.8x 10-4arrow_forward
- A compound X is to be determined by UV/visible spectrophotometry. A calibration curve is constructed from standard solutions of X with the following results: - 0.50 ppm, A = 0.24;- 1.5 ppm, A = 0.36;- 2.5 ppm, A = 0.44;- 3.5 ppm, A = 0.59; and- 4.5 ppm, A = 0.70. Find the following:A. Slope and intercept of the calibration curveB. The mean concentration of the solution of unknown X concentration if the absorbance of 3 replicates are A = 0.29, A = 0.30 and A = 0.32.C. The standard deviation in the concentration of Xarrow_forwardHh.130.arrow_forwardIdentify the following in the given IR Mass spectrum. Compound 1 Mass Spectroscopy: Interpretation of peaks:arrow_forward
- Using the calibration curve y=0.146x+-0.368 find the the quantity of unknown protein that gives a measured absorbance of 0.918 when a blank has an absorbance of 0.138.arrow_forwardInterpretation of the peaks?IUPAC Name / Trivial Name of the compound?arrow_forwardDetermining the concentration of unknown solution using uv-vis spectroscopy. The absorbance vs concentration has an equation of straight line of y=8.4052x+0.0002 with r2=1. The unknown solution's absorbance is 0.150. From 75 mL sample, A 15 mL aliquot was examined. The 15 mL aliquot was mixed with 15 mL 1% percent by mass over volume HCl and was diluted to 40 mL with water. What is the concentration of the solution in the 75 mL sample?arrow_forward
- 3. The lead in a swab sample, lead standards, together with a blank were made up in 5.00 mL volumetric flasks using 0.2 % HNO3. 20 μL aliquots of these solutions were injected into the spectrophotometer and the absorbance measured at 217 nm. The following results were obtained. lead / ppb Absorbance 0 0.0591 10.00 0.0858 50.00 0.1926 100.0 0.3260 150.0 0.4594 200.0 0.5929 Swab sample 0.3700 (a) Determine the amount of lead in the swab sample in μg.arrow_forwardA food supplement is analyzed by Atomic Absorption Spectroscopy to know its Ca content. A 10 ppm standard registers an absorbance of 0.448. A 4.45 g sample is calcined, the ashes are dissolved with 10 mL of acid, and the solution is finally made up to 50 mL; the absorbance reading was 0.325. How many mg of Ca are in 100 g of the dietary supplement?arrow_forwardplease explain which compound this isarrow_forward
- Chemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningPrinciples of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning