TLC Post Lab

If all of the components have a reasonably similar size and molecular weight, which of the suspected components is the most polar?     X     Y     Z      It is impossible to judge

Qs4. This is a TLC analysis of 3 individual compounds. The plate was run in 20 % ethyl acetate, 80% hexane solvent mixture (eluent). Draw a schematic TLC plate for the same compounds, but when the eluent is 40% ethyl acetate, 60 % hexane. Indicate, what is the most polar and least polar compound (A, B, or C) -- A B C

Consider a sample that is a mixture composed of biphenyl, benzoic acid, and benzyl alcohol. The sample is spotted on a TLC plate and developed in a CH2C12-cyclohexane solvent mixture. Predict the relative Rf values for the three components in the sample.  Would biphenyl be closest to the blotted line, then benzyl alcohol, then benzoic acid because these others are increasing in polarity to the non-polar solvent?  Thanks!

Pease indicate the compound that best fits in the blank of the separation scheme below. OH H2N Benzoic Acid Biphenyl Benzocaine Phenol benzocaine phenol biphenyl benzoic acid dissolve in ether; extract with aqueous 19)_ ether aq 20) CO:(g) H2O HIDDEN COMPOUND 1 HIDDEN COMPOUND 2 HIDDEN COMPOUND 3 trace 21) |6.0M М НСI aq NaCl 22). HO Which of the following is the best choice for blank 21 in the given separation scheme? O H2SO4 O pentane O HCI NaHCO3 O H20

Pease indicate the compound that best fits in the blank of the separation scheme below. OH H2N Benzoic Acid Biphenyl Benzocaine Phenol benzocaine phenol biphenyl benzoic acid dissolve in ether; extract with aqueous 19)_ ether aq 20) CO,(g) H2O HIDDEN COMPOUND 1 HIDDEN COMPC HIDDEN COMPOUND 3 trace 21) |6.0 М НСI aq 22) NaCl H20 Which of the following is the best choice for blank 22 in the given separation scheme? phenol O benzocaine O biphenyl water O benzoic acid

Plant pigments in spinach were separated with TLC with cellulose as thestationary phase and 80/20 diethyl ether/acetone mixture as themobile phase. If needed, the solvent structures in the lab Appendix.1. Determine the Rf values of each plant component on this TLC plate.2. Arrange the plant components from most polar to most nonpolar.  Please answer both 1 and 2 (picture below is the same question attached )

Infrared spectrum: interpret all absorptions from the 4000-1400 cm-1 region of the spectrum. Indicate which absorptions come from the ester and which from impurities. Submit the spectrum with your report.

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CI NH 'N' chloroquine CI NH LHO N. N: hydroxychloroquine 5. You attempted to separate chloroquine and hydroxychloroquine using paper chromatography. You used a mixture of benzene and pyridine as your solvent. What results can you expect? O Two bands: hydroxychloroquine will have a higher Rf than chloroquine One band: Both will have equal Rf Four bands: The enantiomers of each analyte will appear as separate bands Two bands: chloroquine will have a higher Rf than hydroxychloroquine

Fully explain what the data in IR and GC-MS spectra mean in the dehydration of 2-Methylcyclohexanol .   GC-MS data (gas chromatography): Illustrated in picture  *ignore peak at 8.87 minutes Peak 1 mass = 96.2 (1-methylcyclohexene) Peak 2 mass = 96.2 (3-methylcyclohexene) Peak 3 mass = 114.2 (impurity) IR Spectra (Infrared Spectroscopy): Illustrated in picture.

1. What should you do if H;SO4 contacts your skin? pyright Cata Education 220 2. When should you stop the distillation process for this procedure? 3. With 85 % H;SO, by volume in water being used in the reaction, how many moles of water will be added to the reaction when 1.25 mL of 85 % H;SO, is added? 4. What peaks in the IR spectrum would indicate the loss of 1-hexene and the formation of 2-hexanol?

identifying all of the mistakes in the separation scheme of 2-methylocta-4,6-dien-1-amine

Which of the compounds would have the shortest retention time on a non-polar GC column? OH HO Hydroxymethyl- cyclohexanol MW: 114 bp: 183 2-Hydroxyethyl- cyclohexanol MW: 144 Methylcyclohexane Methylacetate MW: 98 bp: 101 mp: -127 d: 0.77 MW: 74 mp: -43 d: 0.93 bp: 270 mp: not available d: 0.98 bp: 57 mp: not available d: 0.98 Compound 4 Compound 2 Compound 3 Compound 1

6) You are given a mixture of organic compounds suspected of containing various amines (e. g. 4-chloroaniline). What is the best way to quickly separate these amines from the other organic compounds? a) Perform a fractional distillation on the mixture. b) Benchtop silica gel column chromatography. c) Dissolve the mixture in an organic solvent and treat the solution with aqueous HCI. d) Dissolve the mixture in an organic solvent and treat the solution with aqueous NaOH.

1. Answer true or false for each statement: a) A TLC analysis is sufficient to characterize the purity of a compound. b) Carboxylic acids containing six or more carbon atoms per molecule are more soluble in2.5 M sodium hydroxide than in diethyl ether. c) Phenols containing six or more carbon atoms per molecule are more soluble in 2.5 M sodium hydroxidethan in diethyl ether. d) Benzoic acid and p-nitroaniline form water-soluble salts, whereas naphthalene does not. e) TLC analysis is the method of choice to determine the type of solid phase and eluent system that is required for a column chromatography separation. f) Mineral oil is an inappropriate heating fluid for determining the boiling points of samples that exceed 200°C (760 torr)? g) A heating bath containing mineral oil should not be used to determine the melting points of solids meltingabove 200 °C

Would the solvent system used be effective in separating the two compounds with a column? ---4--4-- R 0.50 R0.30 No, the Rf values are too close together No, there should be more lanes on the TLC plate Yes, the image illustrates two different compounds O Yes, multiple of each type of compound are shown on the plate

Answer last 3

A mixture of tert-butylbenzene and acetophenone is adsorbed onto a silica gel chromatography column and eluted with a moderately polar solvent such as dichloromethane. Match each statement to the appropriate category. least polar tert-Butylbenzene elutes first most polar elutes last Answer Bank Acetophenone

Question is about a TLC analysis of spinach pigments

1. Which compound will have the largest Rf value on a TLC plate using 10% ethyl acetate/hexane as a developing solvent: 3- decanone or 3- decanol, toluene or benzoic acid, cyclohexane or cyclooctanone? Explain why?

Need help with question 2: Which one is the more polar component? Explain.

For question below the separation scheme, please indicate the compound that best fits in the blank of the separation scheme . Hint: s = solid, I = liquid, g = gas and aq aqueous. 4-methylacetophenone soluble aluminum salt (A1C13 destroyed by aqueous HC1) acetic acid (from any unreacted acetyl chloride) trace toluene hydrochloric acid water methylene chloride aq soluble aluminum salt acetic acid hydrocholic acid water multiple Extractions with water and methylene chloride organic 4-methylacetophenone methylene chloride trace toluene trace acetic acid, and H₂O trace 3) organic 4-methylacetophenone methylene chloride trace toluene trace water extract with aqueous aq 5) sodium chloride water CO₂(8)

Record your absorbance data for the YELLOW and RED dyes below. Calculate the dye concentration in mM for each cuvette using M1V2 = M2v2 . Remember the concentration of stock solutions (100^ % dye) is 0.020 mM(mM= millimolar =mm /L). Data for YELLOW: peak absorbance used on spectrophotometer =420nm Cuvette 1 - 100% dye = 0.680 absorption Cuvette 2 - 75% dye = 0.510 absorption Cuvette 3 - 50% dye = 0.340 absorption Cuvette 4 - 25% dye = 0.170 absorption Data for RED - peak absorption used on spectrophotometer = 500nm Cuvette 1 - 100% dye: 0.621 absorption Cuvette 2 - 75%: 0.466 absorption Cuvette 3 - 50% dye: 0.311 absorption Cuvette 4 - 25% dye: 0.1555 absorption

additional information on strengths oj 2. At the end of the extraction lab that you will conduct in a few weeks, you will repeat this TLC experiment. Your task that day will be to use extraction to separate a mixture of benzoic acid, 2-naphthol, and 1,4-dimethoxybenzene. Explain how TLC could be used to demonstrate successful separation of a mixture into individual compounds.

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1. Define λmax and explain why it is desirable to do the experimental procedure at λmax? 2. around what absorbance would you expect the λmax to be with each color solution? (Blue, green, red, yellow) 3. a pipet is used to make the solution dilutions in lab. suppose in making the dilution, additional distilled water is accidentally added. Will the concentration of the solution be higher or lower that disered? explain.