Construct a calibration curve: (a) Subtract the blank value (9.1) from all other values (this means that your first data point will be 0,0). Then use the LINEST calculation of least squares to find the slope and intercept and their uncertainties. slope 869 intercept (b) Replicate measurements of an unknown gave 152.1, 152.4, 153.9, and 152.7 mV, and a blank gave 9.1, 9.4, 10.6, and 9.0 mV. Subtract the average blank from the average unknown to find the average corrected signal for the unknown. 143.25 Check the number of significant figures. (c) Find the concentration of the unknown and its uncertainty.

Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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There is a Canvas AUDIO tutorial available for this problem. This question requires the use of a spread sheet (Excel) to calculate the LINEST uncertainty in the Linear Least
Squares best fit line, and the associated unknown sample. You'll be reproducing the calculations in Figure 4-13 in the 7th Addition of Harris. The instructions for using LINEST
are on the previous page. Here are mass spectrometric signals for methane in H2.
CH4 (vol %): 0
0.062 0.122 0.245 0.486 0.971
1.921
Signal (mV): 9.1 47.5
95.6 193.8 387.5 812.5 1671.9
Construct a calibration curve: (a) Subtract the blank value (9.1) from all other values (this means that your first data point will be 0,0). Then use the LINEST
calculation of least squares to find the slope and intercept and their uncertainties.
slope
869
intercept
(b) Replicate measurements of an unknown gave 152.1, 152.4, 153.9, and 152.7 mV, and a blank gave 9.1, 9.4, 10.6, and 9.0 mV. Subtract the average blank from
the average unknown to find the average corrected signal for the unknown.
4.0 143.25
Check the number of significant figures.
(c) Find the concentration of the unknown and its uncertainty.
0.19
+ 0.01
vol%
Transcribed Image Text:There is a Canvas AUDIO tutorial available for this problem. This question requires the use of a spread sheet (Excel) to calculate the LINEST uncertainty in the Linear Least Squares best fit line, and the associated unknown sample. You'll be reproducing the calculations in Figure 4-13 in the 7th Addition of Harris. The instructions for using LINEST are on the previous page. Here are mass spectrometric signals for methane in H2. CH4 (vol %): 0 0.062 0.122 0.245 0.486 0.971 1.921 Signal (mV): 9.1 47.5 95.6 193.8 387.5 812.5 1671.9 Construct a calibration curve: (a) Subtract the blank value (9.1) from all other values (this means that your first data point will be 0,0). Then use the LINEST calculation of least squares to find the slope and intercept and their uncertainties. slope 869 intercept (b) Replicate measurements of an unknown gave 152.1, 152.4, 153.9, and 152.7 mV, and a blank gave 9.1, 9.4, 10.6, and 9.0 mV. Subtract the average blank from the average unknown to find the average corrected signal for the unknown. 4.0 143.25 Check the number of significant figures. (c) Find the concentration of the unknown and its uncertainty. 0.19 + 0.01 vol%
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