The drug Librium gives a polagraphic wave with E1/2 = -0.265 V (vs SCE) in 0.05 M H;SO4. A 50.0 mL sample containing Librium gave a wave height of 0.37 µA. When 2.00 mL of 3.00 mM Librium in 0.05 M H2SO4 was added to the sample, the wave height increased to 0.80 µA. Find the molarity of Librium in the unknown. Hydrogen peroxide in dilute concentrations can be analyzed by differential pulse polarography. Calibration led to the following relationship la = (7.002 x 107 nA )7[H,02] – 1.500 nA M. Find the hydrogen peroxide concentration in ppb for an unknown that gave a peak current of 300.0 nA.

The drug Librium gives a polagraphic wave with E1/2 = -0.265 V (vs SCE) in 0.05 M H;SO4. A 50.0 mL sample containing Librium gave a wave height of 0.37 µA. When 2.00 mL of 3.00 mM Librium in 0.05 M H2SO4 was added to the sample, the wave height increased to 0.80 µA. Find the molarity of Librium in the unknown. Hydrogen peroxide in dilute concentrations can be analyzed by differential pulse polarography. Calibration led to the following relationship la = (7.002 x 107 nA )7[H,02] – 1.500 nA M. Find the hydrogen peroxide concentration in ppb for an unknown that gave a peak current of 300.0 nA.

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

Chapter10: Atomic Emission Spectrometry

Section: Chapter Questions

Problem 10.11QAP

See similar textbooks

Similar questions

The drug Librium gives a polarographic wave with E1/2 5 20.265 V (versus S.C.E.) in 0.05 M H2SO4. A 50.0-mL sample containing Librium gave a wave height of 0.37 mA. When 2.00 mL of 3.00 mM Librium in 0.05 M H2SO4 were added to the sample, the wave height increased to 0.80 mA. Find the molarity of Librium in the unknown.
The transmittance of a solution measured at 590 nm in a 1.5-cm cuvette was 76.2%. (a) What is the corresponding absorbance?(b) If the concentration is 0.0802 M, what is the absorptivity of this species at this wavelength? (c) If the absorptivity is 10,000 L mol-1 cm-1, what is the concentration?
Solutions of cobalt (II) ions have a magenta color with a molar absorptivity constant (e) value at 511 nm of 5.87 M-1cm-1. A 0.500 mL sample is transferred from a 50.0 mL stock solution of Co(NO3)2 and diluted with water to a final volume of 7.50 mL. The dilution had an absorbance value at 511 nm in a standard cuvette (1.00 cm light path) of 0.382. Calculate the mass of Co(NO3)2 contained in the original 50.0 mL stock solution.
Suppose that you are trying to measure the concentration of SO2 in air. To do that, you followed the para-rosaniline method. The SO2 was collected in a 10-ml solution of HgCl4 2- then diluted to 25 ml after the addition of the appropriate reagents. The absorbance owas measured at 650 nm in a 2.0-cm cell, yielding a value of 0.535. A standard sample was prepared by substituting a 1.00 mL sample of a standard solution containing the equivalent of 15.00 ppm SO2 for the airsample. The absorbance of the standard is found out to be 0.191. Report the concentration of SO2 in the air in parts per million. The density of air is 1.19 g/L
The measures absorbance of a solution with a pathlength of 1.00 cm is 0.544. If the concentration is 1.40 x 10^-3 M, what is the molar absorptivity for this analyte?
A solution containing 5.54 ppm KMnO4 exhibits72.5 %T in a 1.50-cm cell at 520 nm. A. Calculate the absorbance of the solution. B. Calculate the molarity of potassium permanganate. C.
The accuracy of a spectrophotometer can be evaluated by preparing a solution of 60.06-ppm K2Cr2O7 in 0.0050 M H2SO4 and measuring its absorbance at a wavelength of 350 nm using a cell with a pathlength of 1.00 cm. The absorbance should be 0.640. What is the molar absorptivity of K2Cr2O7 at this wavelength?
A 131.7 mg sample of powdered Carbamazepine tablets was boiled with ethanol, filtered and then made up to 100 mL with ethanol. 5 mL of this solution was then diluted to 250 mL with ethanol and the absorbance at 285 nm found to be 0.486 in a 1cm path length cell.Calculate the content (% m/m) of Carbamazepine in the powder, taking A(1%, 1 cm) as 490.(State your answer to 1 decimal place and include the units)
Barium sulfate from a 1.300-g sample was contaminated with 9.4 mg of Fe2(SO4)3 and weighed a total of 314.0 mg. Calculate a) the apparent percent BaSO4 (Apparent – the value of analyte concentration obtained when the interference is not considered) b) the true percent BaSO4
Give the solutions of the following;1. Calculate the effective absorptivity and molar absoptivity for manganese is a potassium permanganate solution that contains 0.10g of manganese in 100 mL has an absorbance of 0.434 using a 1.5 cm cell at a wavelenght of 550 nm. Molar Mass: Mn=54.94Answer: Effective absorptivity= 2.89 cm-1 g-1 L ; mOLAR ABSOPTIVITY= 159 cm-1 mol-1L 2. Manganese is determined colorimentrically as permanganate by measuring the absoprtion of monochromatic green light. A standard solution in an absoption cell 5.00 cm long absorbs 10.0% of the light, while an unknown sample in a cell 1.00 cm long absorbs 50.0% of the light. The standard solution contains 2.00 mg of Mn per liter. What is the concentration (g/L) of the Mn in the unknown? Ans= 0.0657 g/L3. The drug tolbutamine (mm=270) has a molar absorptivity of 703 AT 262 nm. One tablet is dissolved in water and diluted to a volume of 2L. If the solution exhibits an absorbance in the UV region at 262 nm equal to 0.678…
The absorption coefficient of O2 in seawater at 0°C is 1.7 mmol/L.What is the concentration of O2 if the O2 partial pressure is 0.1atm? Express your answer first in mmol/L, then in mL/L.
The ultraviolet spectrum of aspirin shows a secondary absorption band at 271 nm. If a solution of aspirin in water, with a concentration of 1×10-4 molar solution is examined at 271 nm, what will be the absorbance reading (ℇ = 1000) and what will be the intensity ratio, IO/I, respectively?