Use the best fit line to compute the molar absorptivity coefficient for the dye.
ID: 510035 • Letter: U
Question
Use the best fit line to compute the molar absorptivity coefficient for the dye. Do not use the the beer law. Consider how the equation for the best fit line correlates with the beer lambert law?
Info:
best fit line is :
y=(slope plus or minus uncertainty of slope)x + (intercept plus or minus uncertainty of intercept)
beers law: measure absorbance of specific wavelength = molar absorptivity coefficient x path of length of cuvette cm (dont have this so why we are not to use this) x the analyte concentration.
DATA:
slope is 20667 AND the uncertainty slope is 1407.05
intercept is 0.097 and the uncertainty intercept is 0.02619
X(conc of std M) - and Y is absorbance value
X- of first point is 3.3E-06 and Y is 0.12
X of middle point is 1.5E-05 and Y is 0.42
X of final point is 3.0E-05 and Y is 0.70
Thank you ahead of time.
Explanation / Answer
Beer’s Law plot is concentration versus absorbance. The slope of the graph equals the molar absorptivity coefficient, l. usually pathlength = 1 cm
Hence the molar absorptivity coefficient = slope of the graph = 20667 = 2.0667 M-1 cm-1
The equation for the best fit line is
y= mx + c wher m-slope plus or minus uncertainty of slope c-intercept plus or minus uncertainty of intercept
beer law is A = lc + 0
comparing two equations we get m=l and c=0
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.