TLC

96 results

Chemistry!!!

1.)The silica that makes up the stationary phase in TLC chromatophraphy is more polar than the mobile phase. What then might the relative positions of the analgesics on the developed TLC plate tell you about the polarity of these molecules? Does this match the expectations ...

chemistry

How can you tell which mobile phase is more polar in TLC? (hexane/ethyl acetate/ethanol vs. isopropanol/ammonia)? the hexane/ethyl acetate/ethanol travelled up the TLC faster, does this make it more polar? The TLC is silica gel!

Chemistry

Choccamine and mintanol have Rf values of 0.81 and 0.21 respectively. What would the distance in centimetres (cm) between the two compounds be if the TLC was run on a TLC plate where the solvent front moved 8.9 cm from the baseline?

TLC error

When a TLC plate was developed, the solvent front ren off the top of the plate. why?

Organic Chem

What is the problem of spotting TOO much sample on a TLC plate initially? Also, why is it bad to have too much solvent in the TLC jar?

chemistry

Q#1:what would you look for in a tlc experiment to determine whether or not your sample was pure? Q#2:could you determine the extent to which your sample may be contaminated with the tlc technique?

Chemistry - thanks

In a thin layer chromatography (TLC)experiment,the TLC plate was pre-developed in the development chamber containing the mobile phase (to remove any contaminants before use),then air dried. On the same day,the TLC plate was then spotted with the sample & standard and placed in...

Thin Layer Chromotography

Can you use TLC to distinguish various isomers from one another? In what kind of substance can you NOT distinguish the isomers from each other? i think it is not possible to distinguish If I have an unknown sample containing several ketones and want to use TLC to identify the ...

science(chemistry)

I have a question about TLC plate solvents. What solvents will leave stains on a plate with a TLC plate out of the ones below and why?) (n-Octane, n-Hexane, Decane, Acetone, 1-Propanol, 2-Propanol, Ethanol, Toluene, Cyclohexane, Methanol, n-Heptane, n-Pentane, Butanol) I saw 2...

Chemistry

You and another student were each given an unknown compound. Both samples contained colorless material. You each used the same brand of commercially prepared TLC plate and developed the plates using the same solvent. Each of you obtained a single spot of Rf=0.75. Were the two ...

Organic Chemistry

I spotted a commercial TLC plate, coated with silica gel, with a pure benzoin solution. After running the TLC plate in methylene chloride, the benzoin separated into two different spots. Rf values are 0.6 and 0.9. What explains this? A pure material should have only one spot ...

Chem---DrBob222

-----Chromatograph----- Carrying out TLC on colorless compounds. Give two examples of methods to use in order to visualize the spots on the plates. Carrying out TLC with a mixture of two compounds A and B. A is less polar than B. on a reverse phase plate which compound would ...

chemistry

How can you tell which mobile phase is more polar in TLC? (hexane/ethyl acetate/ethanol vs. isopropanol/ammonia)? the hexane/ethyl acetate/ethanol travelled up the TLC faster, does this make it more polar?

Chemistry-help needed

I have a question on thin layer chromatography (TLC). My mobile phase (i.e. developing solvent) is a mixture of 2 non-polar solvents. After preparing the mobile phase, is it necessary to pour some into the developing chamber to saturate the chamber or should we only pour the ...

chem

The Rf value of compound A is .34 when the TLC plate is developed in hexane and .44 when the plate is developed in diethyl ether. Compound B has an Rf value of .42 in hexane and .60 in diethyl ether. Which solvent would be better for seperating a mixture of compounds A and B ...

Chemistry

Consider the following errors that could be made when running TLC. Indicate what should be done to correct the error. a) a two-component mixture containing 1-octene and 1,4-dimethylbenzene gave only one spot with an Rf value of .95. The solvent uses was acetone. b) a two-...

chemistry

How are the spots on the TLC plates observed?

chemistry

How to know if in TLC and HPLC if it is going forward or reverse?

Chemistry

Consider the following errors that could be made when running TLC. Indicate what should be done to correct the error. a) a two-component mixture containing 1-octene and 1,4-dimethylbenzene gave only one spot with an Rf value of .95. The solvent uses was acetone. b) a two-...

Chemistry/ OChem

Consider the following errors that could be made when running TLC. Indicate what should be done to correct the error. a) a two-component mixture containing 1-octene and 1,4-dimethylbenzene gave only one spot with an Rf value of .95. The solvent uses was acetone. b) a two-...

science(chem)

[b]1.[/b]Is TLC a qualitative or quantitative analysis? Is there any way that it can be both? Explain. ~I say it can be both since it can be used to go and determine what exactly is in a sample of mixed compounds which would be qualitative analysis. It can also be quantitative...

pharmacy

suggest a technique , other than tlc, to confirm the purity of the samples

Mobility and Rf

We did a column chromatography then a TLC on extracted spinach pigments. Question: Why are the chlorophylls less mobile on column chromatography and why do they have lower Rf values than the carotenes? My answer: The chlorophylls are more polar than the carotenes so they ...

Chemistry

Can anyone please tell me what can you say about the purity of the compound extracted based on your TLC results? Thanks

Organic Chemistry

Why would the presence of crystals of sample at the starting line cause streaking on a TLC plate?

Sample purity

Question: A student spots an unknown sample on a TLC plate and develops it in pentane solvent. Only one spot, for which the Rf value is 0.05, is observed. Is the unknown a pure compound? What can be done to verify the purity of the sample using TLC? My answer: It's not ...

Organic Chemistry Lab

How do we correct the problem if during TLC development the solvent ran off the plate?

Chemistry

List in increasing order of expected Rf values in a TLC experiment: salicylic acid, toluene, and benzophenone.

science(chemistry)

I have a question about solvent evaporation. If I had an organic layer and an aqueous layer in an unknown mixture of liquids and wanted to obtain the solid of a compound(s) dissolved in the layers, is it reasonable to assume that I can run the compound in the IR spectrometer (...

Organic Chemistry

Thin Layer chromatography TLC experiment What does it mean when it says with to much sample the spots will tail

chemistry

why we just see a light spot of benzaldehyde after tlc in iodine chamber which soon vanishes and does not appear again?

Purity

The question asked is: Using yur results as a guide, comment on the purity of the material in the green and yellow bands. (from a TLC of spinach extraction pigments.) I'm not quite sure what they want here and my plate is in the lab, not here. There were yellow and green bands...

chemistry

why do different compounds give different retention factors (Rf values) in thin layer chromatography (TLC)

TLC purity

Question: A student spots an unknown sample on a TLC plate and develops it in dichloromethane solvent. Only one spot, for which the Rf value is 0.95, is observed. Does this indicate that the unknown material is a pure compound? What can be done to verify the purity of the ...

Chemistry

How do i calculate plate number, distribution constant, mobile phase and stationary phase volume for tlc not HPLC/ GC

Spinach

I did a column chromatography on spinach and then a TLC. On the TLC I got five visible bands of colors. On the extracted yellow substance I got one yellow band (carotene) and on the green I also got only one green band. I thought there would be more bands on the green but ...

chemistry

see if on tlc silica if the polar solvent moves slowly then does even polar substances rf value is low? and the nonpolar rf is high?

Chemistry

suppose you carry out a TLC separation of acetaminophen and phenacetin on silica gel using a non polar developing solvent. which should have a higher Rf value, and why?

accounting

how can i tell which users are internal or external? like bank mangaer parent owner toy suppier cleaner contracted by tlc daycare canada customs and revenus agency

Organic Chemistry

Identify the error in the following scenario and indicate how you would fix the error: A TLC of a two component mixture of pentene and 1,3-diethylbenzene was run in acetone. An Rf value of 0.90 was reported.

Organic Chemistry 1

Why does iodine absorb organic molecules? This question is referring to the effect of the iodine chamber used in TLC.

Organic chemistry

In order to identify a compound using TLC it is necessary to spot a sample of the pure compound. Why is this necessary?

Chemistry

In order to identify a compound using TLC it is necessary to spot a sample of the pure compound. Why is this necessary?

TLC error correction

Question: Consider the following errors that could be made when running TLC. Indicate what should be done to correct the error. A. A two-component mixture containing 1-octene and 1,4-dimethylbenzene gave only one spot with an Rf value of 0.95. The solvent used was acetone. In ...

science(chem)

Consider the following errors that could be made when running the TLC. Indicate what should be done to correct the error. a) A 2 component mixture containing 1-octene and 1,4- dimethylbenzene gave only 1 spot with and Rf value of 0.95. The solvent used was acetone b) A 2 ...

ochem lab

this deals with TLC chromatography: if 2 compounds have same Rf under identical conditions, does it show that they have identical structures? i think it does. but im not sure why. thanks mucho.

organic chemistry

when 2 propanol was used as the developing solvent, two substances moved with the solvent front (Rf=1) during TLC analysis on a silica gel plate. can you conclude that they are identical? if not what additional experiments would you perform?

Organic Chem Lab

If I have separate solutions of the compounds benzoic acid and benzaldehyde, and they are spotted on an alumina gel TLC plate and run using CH2Cl2 as the eluant, which compound will have the higher Rf value? Explain.

Chemistry- polarity

Is 2,4-Hexadiyne-1,6-diol a polar or non-polar compound? I think it is non-polar, based on the the high retention factor (0.89) I got from the TLC.

TLC peru balsam

what is the rf value for peru balsam in order of identification?

Ochem Lab

why is it important to spot samples directly on the marks made on the TLC plate? This is for Thin Layer Chromotography. Is this important so that the solvents move directly up the plate and can be identifies easily? Thanks

Lab conclusion- HELP!

I' am currently trying to wrie a couple of lab conclusions and having a hard time coming up with good points to make for the following lab experiment: Thin layer chorotography If anyone has a few minutes to give me a couple tips on how to improve this. I think it sounds like a...

Chemistry

Chromatography How can I tell which of two mobile phases is more polar? Does the fact that one solvent (e.g. isopropanol/ammonia) moves up the TLC plate slower than another solvent (e.g. hexane/ethyl acetate/ethanol)? Or should I look at how far up the dyes have moved?

Chemistry

Chromatography How can I tell which of two mobile phases is more polar? Does the fact that one solvent (e.g. isopropanol/ammonia) moves up the TLC plate slower than another solvent (e.g. hexane/ethyl acetate/ethanol)? Or should I look at how far up the dyes have moved?

A&P II

I have 2 problems/questions I am unsure of the answers. The first one is "how would you demonstrate the Valsalve maneuver using the model lung?" and 2. If a woman is breathing rapidly and deeply after exercise, would TLC, RV, TV, IRV, and ERV stay the same, increase or ...

Organic Chemistry TLC Chromatography

If you have 5.6 ml of 95:5 ethyl acetate, how many ml of 85:15 ethyl acetate can you make? Assume unlimited supply of pure ethyl acetate.

anatomy

I have 2 problems/questions I am unsure of the answers. The first one is "how would you demonstrate the Valsalve maneuver using the model lung?" and 2. If a woman is breathing rapidly and deeply after exercise, would TLC, RV, TV, IRV, and ERV stay the same, increase or ...

TLC

The following two solvents systems were found to separate compounds x and y by flash column chromatography: X- hexanes/ethyl acetate 10:1 Y- hexanes/ethyl acetate 10:4 which is more polar X or Y? Which solvent system must be used first?

Biology Question

I have 2 problems/questions I am unsure of the answers. The first one is "how would you demonstrate the Valsalve maneuver using the model lung?" and 2. If a woman is breathing rapidly and deeply after exercise, would TLC, RV, TV, IRV, and ERV stay the same, increase or ...

chemistry

-Suppose you carry out TLC separation of acetaminophen and ibuprofen on silica ggel using a nonpolaar developing solvent. which should have a higher Rf? -Assuming that the drug components whose spots you identified dissolved completely when you stirred the tablet with 1:1 ...

Chemistry

Consider compounds trans-4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone below. Using silica gel TLC plates, which of these two compounds will have the higher Rf value when dichloromethane is the developing solvent? Why? Does it possibly have to do with the polarity?

biology

I have 2 problems/questions I am unsure of the answers. 1. how would you demonstrate the Valsalve maneuver using the model lung? 2. If a woman is breathing rapidly and deeply after exercise, would TLC, RV, TV, IRV, and ERV stay the same, increase or decrease? Thank you for any...

chemistry

For a TLC lab,the stationary phase is the mixture of isopropanol and ammonia or the mixture of hexane,ethyl acetate and ethanol, the stationary phase is silica gel. text some dyes and drugs. what is the relationship between the polarity of molecules and the Rf values?

chemistry

In TLC, why do you spot multiple times? Select one or more correct answers. A. To fill the capillary almost instantly by capillary action. B. So the developing chamber solvent does not evaporate. C. The higher compound concentration facilitates visualization. D. To acheive a ...

Difference?

What is the difference between these two questions? They look the same to me, like they're asking the same thing. Not likely. Question: A student spots an unknown sample on a TLC plate and develops it in dichloromethane solvent. Only one spot, for which the Rf value is 0.95, ...

chemistry

out of orthonitroaniline and paranitroaniline which one will go at the top of TLC plate and why It depends upon the stationary phase and the mobile phase, to some extent; however, o-nitroaniline is LESS polar than p-nitroaniline. A polar adsorbent will hold the para isomer ...

college chemistry

If i have a highly polar mobile phase, what will happen to the non-polar or less polar compounds during chromatography? will they move less up the TLC plate or actually even more because the mobile phase itself is so polar.

ochem

Consider a sample that is a mixture composed of biphenyl, benzoic acid, and benzyl alcohol. Predict the order of elution of the components in this mixture on the TLC plate when solvent system a, b or c is used. a)Cyclohexane: Methylenechloride:100%:0% b)Cyclohexane: ...

Organic Chemistry

What is/are the product(s) of the potassium permanganate reaction with (R)-4-methyl cyclohexene? Is the product a meso molecule, racemic mixture, or other mixture, and if so, what kind of mixture? If the product is a mixture, do you expect the compounds to have the same or ...

Thin layer chromatography

I've done some TLC plates using ethyl acetate with 0.5% glacial acetic acid as a solvent. The structure of these substances looks polar to me. I"m assuming that ethyl acetate is not very polar. Is this correct? Acetaminophen barely travelled any distance while aspirin went 2/...

Chemistry

Each of the solvents given should effectively separate of the following mixtures by TLC. Match the appropriate solvent with the mixture that you would expect to separate well with the solvent. Select your solvent from the following: hexane, methylene chloride, or acetone. (a) ...

Solvents

Question: When a TLC plate ws developed, the solvent front ran off the top of the plate. What should be done to correct the error. Me: The only reason I'm giving you this question to check is that it seems too simple. My answer would be to stop development before the solvent ...

Chemistry

Assume your sample spots are 1 cm above the bottom of the TLC plate. What happens if you put the plate in a developing chamber that has 1.2 cm of developing solvent? A. The solvent will move up the plate by capillary action faster. B. The sample spots will become more ...

Chem Help Please!

You are carryingout TLC on normal phase plates. Compound A has an Rf of 0.4 and compound B of 0.6. What would happen to the Rf values if you increase the polarity of the mobile phase? For the compounds in question 1, you change to running them on reverse phase plates. What ...

Chem Help Please!

You are carryingout TLC on normal phase plates. Compound A has an Rf of 0.4 and compound B of 0.6. What would happen to the Rf values if you increase the polarity of the mobile phase? For the compounds in question 1, you change to running them on reverse phase plates. What ...

Identical compounds?

Question: You and another student were each given an unknown compound. Both samples contained colorless material. You each used the same brand of commercially prepared TLC plate and developed the plates using the same solvent. Each of you obtained a single spot of Rf = 0.75. ...

CHEMISTRY

In TLC, why do you spot multiple times? Select one or more correct answers. A. To fill the capillary almost instantly by capillary action. B. So the developing chamber solvent does not evaporate. C. The higher compound concentration facilitates visualization. D. To acheive a ...

rf value of lycopene

Is the the rf value of lycopene and with what solvent can you use as a mobile phase on a TLC? I don't know the answer here but I looked on the Internet and found something that may get you started. I found the Rf value for lycopene to be between 0.4 and 0.6 and the best mobile...

chemistry

For a TLC lab,the stationary phase is the mixture of isopropanol and ammonia or the mixture of hexane,ethyl acetate and ethanol, the stationary phase is silica gel. text some dyes and drugs. which one of the two mobile phases is the more polar? Actualy I need two pieces of ...

Organic Chemistry

I just finished an organic chemistry lab experiment on separating and analyzing an unknown acid/neutral compound mixture using extraction, recrystallization, TLC, melting point analysis, and IR spectrum. In the instructions, "Obtain an IR spectrum for each of your ...

Organic Chemistry Lab

ISOLATION OF CHLOROPHYLL AND CAROTENOID PIGMENTS FROM SPINACH: What would happen to the Rf values of the pigments if you were to increase the relative concentration of acetone in the developing solvent ? I said the Rf values would be higher because Acetone is more polar than ...

Concentration increase

Question: What would happen to the Rf values of the pigments if you were to increase the relative concntration of acetone in the developing solvent? Note: The development solvent used was 70% hexane - 30% acetone. My answer: Acetone is more polar than hexane so the increase in...

list of rf values

can you give a comprehensive list of rf values. rf: Radio Frequency? I am uncertain what the context of rf is. rf probably is related to chromatography. They are the retention factors for thin layer chromatography; i.e., TLC. I looked on www.google.com an this is what I found...

Chemistry/ OChem

Each of the solvents given should effectively separate of the following mixtures by TLC. Match the appropriate solvent with the mixture that you would expect to separate well with the solvent. Select your solvent from the following: hexane, methylene chloride, or acetone. (a) ...

science(chem)

Concerning TLC plates... 1. why should't I allow the solvent to reach the top of the plate? (I assume it's the same as using paper like I did in gen chem but I'm not sure I know why it shouldn't be allowed to reach the top... what would happen?) 2. why sholdn't the spot sample...

Organic Chem.

When a tlc plate was developed the solvent front ran off the top of the plate, why? A two component mixture containing a dicarboxylic acid and tricarboxylic acid gave only one spot with an Rf value of 0.05. Solvent used; hexane. What went wrong? Solvent runs off the top ...

Science - Chromatography

I performed a TLC of plant pigments in my lab class with a solvent of petroleum ether/ acetone (7:3) and used a silica gel plate. It is expected that the most polar pigments (chlorophyll) will be located near the bottom and the carotenoids near top. In my experiment, it was ...

chemistry

One afternoon, a graduate student set up a silica gel column to chromatograph a mixture of two colourless products whose Rf values were quite close. Suddenly, he realized that he had tickets to the Leafs game that night. He turned the stopcock to stop collecting eluent, put a ...

Solvents

Question: Each of the solvents given should effectively separate one of following mixtures by TLC. Match the appropriate solvent with the mixture that you would expect to separate well with that solvent. Select your solvent from the following: hexane, methylene chloride, or ...

Analgesics

We're doing a TLC analysis of analgesic drugs. One of my prelab questions is: Name some advantages of using acetaminphen (Tylenol) instead of aspirin as an analgesic. They were probably dissolved in methylene chloride amd ethanol and I'm assuming that's because one of these is...

Rf values

Question: 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 dichloromethane-cyclobutane solvent mixture. Predict the relative Rf values for the three components in the mixture. (...

science (chem)

consider a sample that is a mixture of biphenyl, benzoic acid, and benzyl alchohol. The sample is spotted on a TLC plate and developed in a methylene chloride cyclohexane mixture. Predict the relative Rf values for the three components in the sample. For assistance use the ...

science (chem) Rf values

consider a sample that is a mixture of biphenyl, benzoic acid, and benzyl alchohol. The sample is spotted on a TLC plate and developed in a methylene chloride cyclohexane mixture. Predict the relative Rf values for the three components in the sample. For assistance use the ...

More spots

Question: A colorless unknown substance is spotted on a TLC plate and developed in the correct solvent. The spots do not appear when visualization with a UV lamp or iodine vapors is attempted. What could you do to visualize the spots if the compound is the following: C. An ...

Visualizing spots

Question: A colorless unknown substance is spotted on a TLC plate and developed in the correct solvent. The spots do not appear when visualization with a UV lamp or iodine vapors is attempted. What could you do to visualize the spots if the compound is the following: My answer...

Coordination

Is coordination the same as ionic bonding? Sheryl As I understand coordination, as in coordination number, no. It is more covalent or more precisely called coordinate covalent if we are talking abouat the same thing. Then I guess 'salt formation' would be referring to ionic ...

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