(a)
Interpretation:
The value standard deviation during the determination of carbon monoxide in automotive exhaust gas is 0.030ppm on the basis of extensive past experience. The 90% confidence interval for triplicate analysis is to be determined.
Concept introduction:
The formula that will be used-
Here,
N = degree of freedom
s = standard deviation
t = constant
(b)
Interpretation:
The value standard deviation during the determination of carbon monoxide in automotive exhaust gas is 0.030ppm on the basis of extensive past experience. The number of measurement is to be determined when 90% confidence interval is to be 0.50ppm.
Concept introduction:
The formula that will be used-
Here,
N = degree of freedom
s = standard deviation
t = constant
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Chapter A1 Solutions
Principles of Instrumental Analysis
- (a) For use in an iodine titration, you prepare a solution from 0.222 2 (+0.000 2) g of KIO3 [FM 214.001 0 (+0.000 9)] in 50.00 (+0.05) mL. Find the molarity and its uncertainty with an appropriate number of significant figures. (b) Would your answer be affected significantly if the reagent were only 99.9% pure?arrow_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_forward(2) In the Analytical Chemistry Laboratory Mr.Yahiya Al Moqbali wanted to prepare KCI solution. He has dissolved 2.634 (+0.002) g of KCI in a 250.00 (±0.08) mL volumetric flask. Calculate the molarity of the solution and express your answer with its absolute uncertainty and give reasonable number of significant figure. [The formula mass of KCI is 74.5513 (±0.001) amu] (Show your Calculation)arrow_forward
- 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)arrow_forwardAnalytical chemistry is a particular field within the broader spectrum of the chemical sciences, in which many times the focus of analytical experiments is to develop new methods to analyze compounds, either structurally or by determining concentrations of compounds. One of the processes analytical chemists use to determine the exact concentration of a working solution is called standardization. In your own words, describe the differences between a primary, secondary, and tertiary standard, and describe the underlying concept behind the standardization process. Why is it done?arrow_forward(a) The pH of a solution is 5.42 + 0.05. Find [H1] and its uncertainty. (b) What is the relative uncertainty in [H1]? (c) Show that the relative uncertainty depends on the uncertainty in pH, but not on the value of pH.arrow_forward
- 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?arrow_forwardList and define the indicators that are used to assess the performance of a specific analytical method under specified conditions.arrow_forward(a) Show that the formula mass of NaCl is 58.443 (+0.002) g/mol. (b) You dissolve 2.634 (+0.002) g of NaCl in a volumetric flask with a volume of 100.00 (+0.08) mL. Express the molarity of NaCl and its uncertainty with an appropriate number of digits.arrow_forward
- A clinical chemist obtained the following data for the alcohol content of a sample of blood: % C,H OH: o.084, 0.089, and o.079. Calculate the 95% confi- dence interval for the mean assuming that (a) the three results obtained are the only indication of the precision of the method and that (b), from previousarrow_forwardQ3)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.arrow_forwardYou 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.arrow_forward
- Principles of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning