Question

Suppose you get the following data (note: these are not necessarily the data you will get or should expect - they are merely being used to make sure you understand the calculations involved). Construct a plot of absorbance (y-axis) versus concentration (x-axis) from the data above. Determine the slope of the best-fit line. Make sure that the graph goes through the origin (0,0). Since the path length is equal to 1 cm, the slope is equal to the molar absorptivity constant. The constant will have units in terms of % by mass, but this is fine since we will use this constant for the white wine and report the results in terms of % by mass. The molar absorptivity constant is Please enter your results to the correct precision. You measure the absorbance of the white wine (at the same wavelength) and it is 0.47. Determine the concentration of the alcohol in the white wine in terms of % by mass.

Answer 1

\r\n Molar absorptivity calculation A = epsilon Cd = > A = (epsilon d) C In A vs C graph elementof d is slope Slope - y_2 - y_1/x_2 - x_1 = 0.79 - 0.18/20 - 5 elementof d = 0.04 elementof = 0.04 From plot we get y = 0.039 x y = Absorbance = 0.47 x = Concentration 0.47 = 0.039 x x = 0.47/0.034 x = 12.05%