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7. (4 pt.) What two methods were used to visualize the spots on the developed TLC...
Possible Quiz Questions 1 What two methods of visualizing spots on a TLC plate will you use in this Give two reasons why would you predict that the elution solvents (hexanes or acetate) would not be visible under UV visualization? week's lab? ethyl 2. Define R 3. Calculate the R of the spot on the following TLC plate. 4. Which compound in each pair is predicted to have the higher Ri? a. CH3CH2CH2CH2OH and CH3CH2CH2CH28r b. CH3CH2CH2CH2OH and CH3CH2CH2CH2CH2CH2CH3 c....
3) What two methods of visualizing spots on the TLC plate will you use in this lab? Why would you predict that the elution solvents (hexanes or ethyl acetate) would not be visible under UV visualization?
CAN SOMONE PLEASE HELP. above is a picture of two TLC plates with spots on them. could somone PLEASE PLEASE PLEASE help me get their measurmentS (in milimeters) and help me calculate their Rf values!!! I promise to rate u good if you could help!!! Im so confused!!! THANK U SM -solvent front scluent front Acetaminophen (A Afine (caf) Unknown mixture Phenacetin (Phn) Salicyamide (sal) Plate 2 Untuan unknown ixture mixture duplicate spots Plate 1 ASSIGNMENT In this experiment, TLC...
1. How does the sample separate on a TLC plate? 2.What are some ways to visualize a TLC plate? Why may it be necessary to have more than one method to visualize a TLC plate? 3.Describe how to obtain a Retention Factor. What does the retention factor tell you?
4. Consider the following silica gel TLC plac or compounds A, B, and hexines: developed in Fo-o- og a) Determine the Rr values of compounds A, B, and C run on a silica gel TLC plate using hexanes as the solvent b) Which compound, A, B, or C. is the most polar? values if you used acetone instead c) What would you expect to happen to the of hexanes as the eluting solvent? 5) Consider a sample that is a...
During the TLC plate you notice all of the spots remain on the baseline. What is the problem and how would you fix it?
1. (5 pt.) Soon you will synthesize the analgesic acetanilide in lab. It’s m.p. is 114C. What does it indicate about your product if you obtain a m.p. of 103 - 112C. Explain. 2. (6 pt.) Neither aniline nor nitrobenzene is particularly water soluble. However, one is completely soluble in dilute aqueous HCl. Which one is soluble, and explain why? (For maximum credit, provide a chemical equation for your answer.) 3. (5 pt.) Name the two adsorbents that are most...
Common solvents used in TLC analysis are hexane and ethyl acetate, the latter being more polar. A TLC has been performed on a mixture of two compounds. The solvent ran for 3 cm(plate length is 6cm) with 5% ethyl acetate in hexane. The two spots were not resolved, meaning they showed up too close to each other. What can you suggest to possible improve the results of the separation?
4) sketch what a developed and resolved TLC plate of a mixture of benzil, benzoin and hydrobenzoin might look like. Discuss the relative Rf values on your sketched plate 5) In the reduction of benzil with sodium borohydride, 3 compounds are possible: meso-hydrobenzoin, racemic-hydrobenzoin and racemic-benzoin (resulting from incomplete reduction of benzil). Discuss how you determined (or will go about determining) which of these products was produced. Discuss evidence from melting points, TLC and IR spectra.
A TLC plate was run in 1:1 ethyl acetate and hexane, but when developed the plate only showed baseline spots. What change could be made to get the spot(s) to move further up the plate? -Spot a new plate and run again in the same solvent system -Spot a new plate and run in neat hexane -Spot a new plate and run in 1:2 ethyl acetate/hexane -Spot a new plate and run in 2:1 ethyl acetate/hexane