Use graph should look something like this: Complete report sheets using all of t
ID: 531204 • Letter: U
Question
Use graph should look something like this: Complete report sheets using all of the rules for significant figures and Use the Table on p. xv of the lab manual to find uncertainty estimates for all the measured values depending on the source (e.g. analytical balance). Using the above, construct a properly laid out and labeled graph, and print it the out. On the back of the graph, answer the following questions: a. If you measure an unknown sample with an absorbance of 0.167, describe 2 ways you can determine the concentration from the graph? b. Which way gives a more accurate answer? What is the concentration of sample with the absorbance of 0.167?Explanation / Answer
The two ways the absorbance can be measured by
a) in the plot of absorbance vs concentration, draw a horizontal line at 0.167 concentration and intersect the curve. Then draw a vertical line down from the intersection point.
b) from the best fit absorbance = 0.02598*concentration+0.00584, substitute the value of absorbance and determine the concentration.
since second one is the best fit of all the points, second equation is expected to give best result with minimum error.
c) when Absorbance =0.167, 0.167= 0.02598* concentration +0.00584
concentration = (0.167-0.00584)/0.02598=6.2 mg/L ( by equation of best fit). From the method a described above,
concentration = 6.4 mg/L
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