Match Column A with Column B. V Distance traveled by the solvent A. Silica gel G Adsorbent used in TLC B. Eluent v High affinity to stationary phase C. High Rf value v High affinity to mobile phase D. Point of origin v Liquid that comes out of the column E. Low Rf value F. Solvent front G. Silica gel H. Eluate

Match Column A with Column B. V Distance traveled by the solvent A. Silica gel G Adsorbent used in TLC B. Eluent v High affinity to stationary phase C. High Rf value v High affinity to mobile phase D. Point of origin v Liquid that comes out of the column E. Low Rf value F. Solvent front G. Silica gel H. Eluate

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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Ion exchange chromatography consists of? i. stationary phase with a matrix of charged ionizable functional groups ii. mobile phase consisting of a buffer at a certain pH iii. coloured fluorescent dye iv. analyte that requires an optimum wavelength A. ii and iii B. i and iv C. iii and iv D. i and ii
You have 100 mL of solvent available to do an extraction. Which will give a better separation? O A. 1 extraction with 100 mL B. 2 extractions with 50 mL C. 5 extractions with 20 mL O D.3 extractions with 25 mL
5. Which term is INCORRECTLY defined? a. linear range - the range over which the response of an analytical method is proportional to analyte concentration b. dynamic range concentration range over which there is a measurable response to analyte, though the response is not linear c. blank solution - a solution containing all reagents and solvents used in the analysis to which no analyte is deliberately added d. standard solutions - solutions for which the standard deviation is known - 6. True or False: Internal standards correct random error caused by run-to-run variation. a. True b. False
What is the result of applying too much sample to the TLC plate? Select one: Some of the sample moves down instead of up Reduced separation between the spots O The sample moves past the solvent front O The spot does not leave the origin O The sample leeches out into the elution solvent
QUESTION 15 To improve the accuracy of our linear fit between absorbance and concentration, a. add an extra data point to your linear regression where you make the assumption that pure water has an absorbance of zero. b. make sure that you choose a "Linear Regression" curve fit. c. ensure that there are no air bubbles in the cuvette. O d. use the data points only at the lower end of the concentration range because Beer's Law is not applicable for higher concentrations. QUESTION 16 What laboratory equipment do you need to prepare a 0.250 M stock solution of NaCI? O a. buret, graduated cylinder, analytical balance b. beaker, volumetric flask O. volumetric pipet, analytical balance d. analytical balance, volumetric flask
To compensate for a complex or unknown matrix, the ● · · ● A. Calibration curve OB. Standard addition Method O C. Internal Standard Method O D. Dilution method O E. Least-Squares Analysis O F. Standardization method should be used to determine the analyte concentration.
1. What is the planar chromatography and what type of different planar chromatographic methods are available? 2. What is the thin layer chromatography technique and define the mobile and stationary phases used in the technique. Describe how the components are separated from each other using TLC technique? 3. List at least four common uses of TLC technique? 4. Briefly explain the steps involved in TLC analysis. 5. What's the advantage of TLC as compared to the column chromatography? 6. Calculate the Rf values of substances shown below; -0.59 -027
Thin Layer Chromatography -Explain why increasing the polarity of the mobile phase causes all Rf’s to increase. -Explain how Thin Layer Chromatography allows for the separation of the components of a mixture on a TLC plate? Please include equilibrium, stationary and mobile phase, nonpolar and polar annilites, affinitity...which annilites (polar/nonpolar) have greater affinity for stationary or mobile phase? Thank you
2. When separating acetone (an organic liquid) from LiBr (a solid impurity), which would be the most convenient means of separation? a. steam distillation b. column chromatography c. fractional distillation d. simple distillation Your answer:
5. Summarize your conclusions from the TLC simulator. Circle the correct answer in each description about TLC separation of organic compounds on silica gel plates. a) A more polar compound has a lower/higher retention factor. b) A less polar compound has a lower/higher retention factor. c) A more polar solvent causes a lower/higher retention factor. d) A less polar solvent causes a lower/higher retention factor. e) To increase the retention factor of a spot, you should add more ethyl acetate/hexane.
6. Mass spectrometry and UV/Vis absorbance spectroscopy can both be used as detectors for liquid chromatography experiments. a. In simple systems, quantifying the concentration of an analyte is usually easier with UV/Vis than with MS. Explain why. b. Because MS is more sensitive and more selective, we often use it for quantitative analysis anyway. Explain how you would design a quantitative LC/MS experiment.