3. Using the data at right: a. Calculate the absorbance of each sample. You will need to express the %T values as decimals before calculating the logarithms. (e.g., for T = 25%, A = -log 0.25 0.602) b. Use the graph paper on the back of this page (or a spreadsheet) to plot absorbance vs. concentration. Make a proper graph, with labeled axes, uniform scales, etc. Use a ruler to draw the best-fit line. c. Use the graph to find the concentration of the un- known sample. (Draw dotted lines on the graph showing how you found your answer.) CONCENTRATION PERCENT TRANSMISSION 100.0 74.1 54.9 40.7 30.1 22.3 (ppm) 0 100 200 300 400 500 unknown 31.6 ABSORBANCE

3. Using the data at right: a. Calculate the absorbance of each sample. You will need to express the %T values as decimals before calculating the logarithms. (e.g., for T = 25%, A = -log 0.25 0.602) b. Use the graph paper on the back of this page (or a spreadsheet) to plot absorbance vs. concentration. Make a proper graph, with labeled axes, uniform scales, etc. Use a ruler to draw the best-fit line. c. Use the graph to find the concentration of the un- known sample. (Draw dotted lines on the graph showing how you found your answer.) CONCENTRATION PERCENT TRANSMISSION 100.0 74.1 54.9 40.7 30.1 22.3 (ppm) 0 100 200 300 400 500 unknown 31.6 ABSORBANCE

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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4. Which Molecular formula best fits the following MS description? M* m/z = 136 and M at m/z = 138 with approximately a 3 to 1 intensity a. C10H16 b. C9H120 C. C4H9Br d. C6H130C1 "
5. Use the simulation to collect data and sketch the spectrum for Nickel (II) Chloride. Absorbance 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 Wavelength (nm) What color is this solution? a. b. Which primary colors does the solution absorb? C. Which primary colors does the solution transmit (not absorb)?
Sample #1 has an absorbance of 0.300. Sample #2 is the same substance and has an absorbance of 0.600 using the same equipment. What is the relative concentration of the second sample? Select one: a. The concentration of sample #2 is the square root of that of #1. b. The concentration of sample #2 is that of sample #1 squared. c. The concentration of sample #2 is half that of sample #1. d. The concentration of sample #2 is twice that of sample #1.
1. List the concentrations of the stock. [Acetone] 0.6M [lodine] 00025M [HC1] 2. From the computer plot of the data for each trial (absorbance vs. time in seconds), detemine the slope of the best straight line; use the following data table to summarize your results: Table 1. Trial # Acetone, mL lodine, mL HCI, mL AAbs/At ( slope of line) H20, mL A 1.0 1.0 1.0 2.0 -0.0010258xto:34978. t0.0016339x+0.44357 70,00g0217x 0.89112 0. 0013205xto,235271 2.0 1.0 1.0 1.0 1.0 2.0 1.0 1.0 D 1.0 1.0 2.0 1.0 3. Convert stock concentrations to initial concentrations and fill in Table 2: Table 2. Trial # Disappearance Rate of l2 (M/s) -A[L/At (= -slope/730) [Acetone] [lodine] [HCIJ 0.12 0.00050.12 0.24 0.12 10.12 0. coe 5 0.12 0.001 0.12 D 0.00050.24
A colored ion solution has a concentration of 0.200 M with a measured absorbance A = 0.880. Another ion solution made of the same chemicals has an absorbance A = 0.172. What is the concentration of this unknown sample solution?
Can you help me on questions 2 AND 3
Create a calibration curve for the following 4 M concentrations. (0.16 M, 0.080 M, 0.040 M, and 0.016 M.) The data is in the attached image. Note* only use the absorbance points from the highlighted (highlighted in blue) column. It is the column with an absorbance of 442.6.
Please help
Follow-up questions 1. What is the purpose of the lid on the colorimeter? 2. In part 1, why is it necessary to calibrate absorbance at every wavelength? 3. In part 1, the concentration of the CV+ stock solution was 12.5 uM. What mass of CV+ is found in 1 liter of this solution? Give your answer in milligrams. (The molar mass of crystal violet is 407.979g.) 6. 4. What are the effects of the following changes on molar absorptivity? (a) when the concentration of CV+ changes? (b) during the course of the color-loss reaction? (c) when absorbance is measured at different wavelengths? 5. In part 2, what labware or apparatus would you use to prepare solutions for the standard curve? In part 3, what percentage of the NaOH is left at the end of the color-loss reaction, assuming all the crystal violet has reacted? Show your calculation. 6. 7. (a) In part 3, how long is the half-life of the color-loss reaction (show the calculation)? (b) In part 4, is the half-life of the color-loss reaction…
Using the lab instructions and data table with data, please help me complete part 1 and 2 of my lab worksheet
B. Quantitative Spectroscopy Prepare two graphs, %T vs. Concentration and Absorbance vs. Concentration, using the data for the cobalt standards. The concentrations of Cobalt standards 2-4 can be calculated using simple dilution calculations. Concentration should be on the x-axis for each of these graphs. The first should clearly show some curvature while the second should be a linear curve. Using the absorbance graph you can determine the concentration of the unknown. Take the absorbance value for the unknown and find that value on the y-axis. Draw a horizontal line from that point on the y-axis to the plotted line. From the point where the horizontal line intersects the plotted line, draw a vertical line straight down to the x-axis. Record the value from the point where you hit the x-axis as the unknown concentration.
Absorbance is not proportional to which of the following? a. Intensity b. Molar Absorptivity c. Concentration d. Path Length