(a)
Interpretation:
A graph should be plotted using the spreadsheet for given information.
Concept introduction:
Flame emission spectrography is so named because the atoms are exposed to a flame to get the required amount of energy of excitation. This is a classical method and has been widely replaced by the plasma spectroscopies.
(b)
Interpretation:
The least square equation for the given data should be determined.
Concept introduction:
Flame emission spectrography is named so, because the atoms are exposed to a flame to get the required amount of energy of excitation. This is a classical method and has been widely replaced by the plasma spectroscopies.
(c)
Interpretation:
The statistics of the line plotted in option b should be determined.
Introduction:
Flame emission spectrography is so named because the atoms are exposed to a flame to get the required amount of energy of excitation. This is a classical method and has been widely replaced by the plasma spectroscopies.
(d)
Interpretation:
The percentage of Na2O in each given sample and the absolute and relative standard deviations should be determined.
Introduction:
Flame emission spectrography is so named because the atoms are exposed to a flame to get the required amount of energy of excitation. This is a classical method and has been widely replaced by the plasma spectroscopies.
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Chapter 9 Solutions
Principles of Instrumental Analysis
- 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/mLarrow_forwardA chemist obtained the following data for percent lindane in the triplicate analysis of an insecticide preparation: 7.23, 6.95, and 7.53%. Calculate the 90% confidence interval for the mean of the the three data, assuming that (a) the only information about the precision of the method is the precision for the three data. (b) on the basis of long experience with the method, it is believed that s---->σ lindane. (c) If s=0.28 is good estimate of σ, how many replicate measurement should be made in order for the mean for the analysis of sample to be within 0.2% of the true mean 90% of the time.arrow_forwardExactly 5.00 mL aliquots of a solution containing analyte X were transferred into 50.00-mL volumetric flasks and the pH of the solution is adjusted to 9.0. The following volumes of a standard solution containing 2.00 µg/mL of X were then added into each flask and the mixture was diluted to volume: 0.000, 0.500, 1.00, 1.50 and 2.00 mL. The fluorescence of each of these solutions was measured with a fluorometer, and the following values were obtained: 3.26, 4.80, 6.42, 8.02 and 9.56, respectively. ii. Using relevant functions in Excel, derive a least-squares equation for the data, and use the parameters of this equation to find the concentration of the phenobarbital in the unknown solution.arrow_forward
- You have measured the blank for a determination of arsenic in food samples by hydride-generation atomic fluorescence spectrometry. The blank values are: 0.23 ppb, 0.14 ppb, 0.16 ppb, 0.28 ppb, 0.18 ppb, 0.09 ppb, 0.10 ppb, 0.20 ppb, 0.15 ppb, 0.21 ppb As. What is the LOD?arrow_forwardDefine mass spectroscopy and the underlying principle/background of its method for characterizing samples.arrow_forwardA sample of water from the North Sea was analysed by ion-chromatography and the sulfate concentration determined to be 2960 mg/L. A sample of formation water from a reservoir near Shetland was analysed by atomic emission spectroscopy and the strontium concentration determined to be 770 mg/L. If the Ksp value for strontium sulfate is 3.44x10- mol- L-2 predict whether precipitation should occur if 500 ml of the seawater is mixed with 500 ml of the formation water.arrow_forward
- As a forensic toxicologist, you have been given a task on determining amount of cadmium, mercury, chromium, copper and lead metal contents in medicinal herbs using flame atomic absorption spectroscopy (AAS). Hollow cathode lamp (HCL) was selected as radiation source for this analysis. The highest concentration came from lead element followed by chromium and copper, however cadmium and mercury were not detected in the sample. a) Based on your knowledge, conclude whether the above result is valid or not. b) If you are given an option of electrothermal or flame atomizer for above case study, determine which one is suitable and justify your answer.arrow_forwardA sample of body serum is to be analysed for sodium by flame emission spectroscopy. 1.00cm' aliquot of serum was pipetted into each of two 50.0cm' volumetric flasks. The first flask was diluted to volume with deionised water. The absorbance of this first solution was0.350. To the second flask 10.0 cm' of a 25.0 ppm sodium standard was added and the flask made up to volume with deionised water. The absorbance of this second solution was 0.720.(i) Calculate the concentration of the sodium in the body serum in mg dm-3.arrow_forwardPrepare a calibration curve to determine the Pb content in a well water sample using atomic absorption spectrophotometry; the following data were recorded: % T 100 75.2 56.6 42.5 31.9 24.6 13.8 ppm Pb 0 0.2 0.4 0.6 0.8 1.0 1.4 A 50 mL aliquot of well water is taken and diluted twice, the% T reading is taken and a value of 40.6% is recorded. Calculate the ppm of Pb in the well water.arrow_forward
- A sample of water from the North Sea was analysed by ion-chromatography and the sulfate concentration was determined to be 2960 mg/L. A sample of formation water from a reservoir near Shetland was analysed by atomic emission spectroscopy and thestrontium concentration was determined to be 770 mg/L. If the Ksp value for strontium sulfate is 3. 44x10-7 mo? L2 predict whether precipitation should occur if 500 ml of the seawater is mixed with 500 ml of the formation water.arrow_forwardA solution was prepared from an amount n = (0.500 ± 0.005) mol dissolved in a volume V = (250.0 ± 0.5) cm3. What is the absolute uncertainty in the concentration in units of mol dm-3?arrow_forwardA 10.00-g sample containing an analyte was transferred to a 250-mL volumetric flask and diluted to volume. When a 10.00-mL aliquot of the resulting solution was diluted to 25.00 mL it was found to give a signal of o.235 (arbitrary units). A second 10.00-mL aliquot was spiked with 10.00 mL of a 1.00- ppm standard solution of the analyte and diluted to 25.0o mL. The signal for the spiked sample was found to be o.502. Calculate the weight percent of analyte in the original sample.arrow_forward
- Principles of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning