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; 4.5 ppm, A = 0.70. A solution of unknown X concentration had an absorbance of A = 0.50. Find the slope and in te rcept of the calibration curve, the standard error in Y, the concentration of the solution of unknown X concentrat ion, and the standard deviation in the concentration of X. Construct a plot of the calibration curve and determine the unknown concentra tion by hand from the plot. Compare it to that obtained from the regression line.

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; 4.5 ppm, A = 0.70. A solution of unknown X concentration had an absorbance of A = 0.50. Find the slope and in te rcept of the calibration curve, the standard error in Y, the concentration of the solution of unknown X concentrat ion, and the standard deviation in the concentration of X. Construct a plot of the calibration curve and determine the unknown concentra tion by hand from the plot. Compare it to that obtained from the regression line.

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter20: Molecular Mass Spectrometry

Section: Chapter Questions

Problem 20.9QAP

See similar textbooks

Similar questions

A compound Y is to be determined by UV-visible spectrophotometry. A calibration curve is constructed from standard solutions of Y with the following results: 0.20 ppm, A = 0.870; 0.40 ppm, A = 0.840; 0.60 ppm, A = 0.800; 0.80 ppm, A = 0.750; 1.00 ppm, A = 0.700; 1.50 ppm, A = 0.620; and 2.00 ppm, A = 0.530. a. What is the equation of the calibration curve for compound Y? b. What is the linearity of the calibration curve for compound Y?
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: 1. slope and intercept of the calibration curve 2. 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. 3. the standard deviation in the concentration of X
The 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 10-4
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 X
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.
Identify the following in the given IR Mass spectrum. Compound 1 Mass Spectroscopy: Interpretation of peaks: Compound 1 Mass Spectroscopy: MASS SPECTRUM 100 80 60 40 20 0.0- 10 20 30 40 50 60 70 m/z Interpretation of peaks: Rel. Intensity
What structural features of Hydroxypropyl Acrylate (HPA) allow it to be detected by HPLC?
2) In a laboratory study, a calibration was performed using NH4C1 to analyze ammonium spectrophotometrically. The results of the study are given below. According to this, when the 5.0 mL sample containing ammonium is completed to 50 mL with pure water, find the amount of NH4 in the sample whose absorbance was found as 0.12 according to the table. (N: 14 g / mol, H: 1 g / mol, Cl: 35.5 g / mol). Concentration (mg/L) Absorbance 0.01 5 0.05 7.5 0.1 10 0.15 12 0.18
The ppm concentration of Pb2+ in a blood sample were measured with Spectrophotometry. 5.00 mL of a blood sample were taken and this sample gave a signal of 0.301 a.u.. Another 5.00 mL of a blood sample were mixed with 0.50 mL og 1.75 ppm Pb2+. Then, this mixture was diluted to 25.00 mL and this diluted mixture gave a signal of 0.406 a.u.. What is the ppm concentration of a blood sample?
A 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?
A juice concentrate was colorimetrically assayed using Nelson’s test. One milliliter (1.00 mL) of the sample solution and various concentrations of the standard glucose solution were treated with freshly prepared Nelson’s reagent and arsenomolybdate reagent and then diluted to 10.0 mL separately in properly labeled test tubes. Absorbances at 480 nm for distilled water, glucose standard, and for the sample are 0.052, 1.702, and 0.926, respectively. What is the reducing sugar concentration (mg/mL) in the juice concentrate? The equation of the line was plotted to be: y = 1.6656x - 0.0885 0.578 mg/mL 577.9 mg/mL 57.7 mg/mL 5.78 mg/mL
The trendline for a calibration curve is y=4.299x+-0.0001. The absorbance of a solution of the unknown concentration is 0.0812 What is the concentration of the unknown solution in uM