For a concentration technique, Stotal is given as 19.31 ± 0.035, Smb is 0.22 ± 0.008, and kA is 0.154 0.007 ppm, where Stotal is the signal, KA is the method's sensitivity for the analyte and Smb is the signal from the method blank. If we want the absolute percent uncertainty of the concentration CA to be 2.6%, which statement is false below? (Hint: refer to sections 4B.1 and example 4.7 in your textbook) We must improve the uncertainty in kA to 10.004 ppm. O Uncertainty in the method's sensitivity dominates the absolute uncertainty. Improving the signal's uncertainty will improve the absolute uncertainty.

For a concentration technique, Stotal is given as 19.31 ± 0.035, Smb is 0.22 ± 0.008, and kA is 0.154 0.007 ppm, where Stotal is the signal, KA is the method's sensitivity for the analyte and Smb is the signal from the method blank. If we want the absolute percent uncertainty of the concentration CA to be 2.6%, which statement is false below? (Hint: refer to sections 4B.1 and example 4.7 in your textbook) We must improve the uncertainty in kA to 10.004 ppm. O Uncertainty in the method's sensitivity dominates the absolute uncertainty. Improving the signal's uncertainty will improve the absolute uncertainty.

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter16: Applications Of Neutralization Titrations

Section: Chapter Questions

Problem 16.18QAP

See similar textbooks

Similar questions

[References) A method for the determination of the corticosteroid methylprednisolone acetate in solutions obtained from pharmaceutical preparations yielded a mean value of 3.7 mg mL with a standard deviation of 0.3 mg mL. For quality control purposes, the relative uncertainty in the concentration should be no more than 3%. How many samples of each batch should be analyzed to ensure that the relative standard deviation does not exceed 9% at the 95% confidence level? samples
Example 2: You prepared a 0.250 M NH3 solution by diluting 8.45 (±0.04) mL of 28.0 (±0.5) wt% NH3 [density = 0.899 (±0.003) g/mL] up to 500.0 (±0.2) mL. Find the uncertainty in 0.250 M. The molecular mass of NH3, 17.0306 g/mol, has negligible uncertainty relative to other uncertainties in this problem. %3D
Suppose that you used smaller volumetric apparatus to prepare 0.250 M NH3 solution by diluting 84.6 (±0.8) µL of 28.0 (±0.5) wt% NH3 up to 5.00 (±0.02) mL. Find the uncertainty in 0.250 M.
In a volumetric determination of an analyte A, the data obtained and their standard deviations are as follows: Initial buret reading 0.19 mL 0.02 mL Final buret reading 7.86 mL 0.03 mL Sample mass 63.0 mg 0.2 mg From the data, find the coefficient of variation of the final result for the %A that is obtained by using the equation that follows and assuming there is no uncertainty in the equivalent mass. %A= titrant volume x equivalent mass x 100 %/ sample mass Coefficient of variation = Submit Answer % Try Another Version 10 item attempts remaining
A volume of 250 ml of a 0.05 M solution of a reagent of formula weight (relative molecular mass) 40 was made up, the weighing being done by difference. The standard deviation of each weighing was 0.0001 g. 1 (a) What were the standard deviation and relative standard deviation of the weight of reagent used?
A titrimetric method for the determination of calcium in limestone was tested by analysis of an NIST limestone containing 30.15% CaO. The mean result of four analyses was 30.26% CaO, with a standard deviation of 0.085%. By pooling data from several analyses, it was established that s   = 0.094% CaO.a. Do the data indicate the presence of a systematic error at the 95% confidence level?b. Do the data indicate the presence of systematic error at the 95% confidence level if no pooled value for s was available?
EXAMPLE Significant Figures in Laboratory Work You prepared a 0.250 M NH, solution by diluting 8.46 (0.04) mL of 28.0 (10.5) wt% NH, [density=0.899 (+0.003) g/mL] up to 500.0 (+0.2) mL. Find the uncertainty in 0.250 M. The molecular mass of NH3, 17.031 g/mol, has negligible uncertainty relative to other uncertainties in this problem.
A solution is prepared by weighing 5.0000 g of cesium iodide into a 100-mL volumetric flask. The balance used has a precision of 0.2 mg reported as a standard deviation, and the volumetric flask could be filled with a precision of 0.15mL also reported as a standard deviation. What is the estimated standard deviation of concentration (g/mL)?
A young researcher was evaluating a standard method for determining the methylmercury content in blue fin tuna using high performance liquid chromatography (HPLC). She determined the standard deviation (?)(s) for the method to be 0.440.44 ppb and assumed that ?s was a good approximation of ?σ . As a test, she used this method to evaluate the methylmercury content in a National Institutes of Standards and Technology (NIST) standard and determined the unknown amount to be within 0.210.21 ppb (?)(μ) of the known mean with 99% probability. How many replicate measurements of the NIST standard did the researcher perform?
What is a 99% confidence interval uncertainty of the slope when we are given a trendline with a slope of 42.211 and an R² value of 0.9991 for a set of 145 data points?
For the determination of iron in used jet engine oil, 30 analyzes with 3 repetitions each were made by atomic absorption method and the standard deviation was found s=2.4 µg Fe/mL. Since this standard deviation value is close to the ϭ value, the iron concentration of 18.5 µg Fe/mL(a) by a single analysis,(b) as the average of the two analyzes,(c) Calculate the 80% and 95% confidence intervals if found as the mean of four analyses.
What are the differences between systematic and random errors and how do they effect accuracy and precision? In what circumstances would you use standard addition (versus a normal calibration curve) to determine the amount of an analyte in a sample? A urine sample, containing analyte Z is analysed by the standard addition method where 5 mL of the original sample was mixed with increasing amounts of a Z standard and each solution diluted to a volume of 50 mL prior to analysis. A plot of the final concentration of the standard in each of the 50 mL samples (x axis) versus The measured signal from the analysis of each 50 mL sample (on y axis) produced a straight line with the general equation: y = 44.72x + 4.06 what was the final concentration of Z in the 50 mL standard addition sample? what was the initial concentration of Z in the original urine sample?