Experiment 9_ Column Chromatography

19. What is thin layer chromatography (TLC) LEAST useful for from the list below? A) To determine if crystallization or distillation may be more effective for a separation B) To determine the number of components in a mixture C) To determine the appropriate solvent for column- chromatographic separation D) To monitor the progress of an organic synthesis reaction 14. The solubility of salicylic acid in water is 7.8g/100ml at 100°C and 0.25g/100ml at 25°. Estimate how much water is needed to recrystallize a 19g sample of salicylic acid? A) 150ml B) 250ml C) 300ml D) 400ml

The uses of thin layer chromatography are: 1) To identify unknown compounds 2) Determine purity of products 3) Analyze reaction mixtures 4) To waste time in lab 5) Determine the melting point of the product U 6) Put an astronaut on the moon.

How does ammonia, dimethylglyoxime (DMG), and 8-hydroxyquinoline (8HQ) interact with your cations, leading to the evolution of colored species?   Context: Paper chromatography experiment (separation of inorganic cations) with a 9:1 acetone/ HCl solvent

1. How does chromatography separate the components of leave samples? 2. Can you use chromatography to purify a mixture? why? 3. What is Rf value and its significance in chromatography?

Identify the detectors in gas chromatography that can be used for the detection of each type of analyte. More than one detector may be appropriate for a given analyte, and a given detector may be appropriate for more than one type of analyte. compounds ionized by UV radiation sulfur or nitrogen containing compounds halogenated compounds flame ionization Answer Bank mass spectrometer nitrogen and phosphorous containing compounds thermal conductivity electrolytic conductivity hydrocarbons electron capture thermionic photoionization

The paper used in chromatography is made of molecules with___parts A polar  B nonpolar

Explain the following Chromatography (for drug analysis) Thin-layer chromatography (TLC) Gas chromatography (GC) Liquid chromatography (LC) (i.e, high performance liquid chromatography or HPLC)

Three students did a chromatography experiment, where Rf = distance of solute / distance of solvent. What could be the possible errors why student 3 had results that are quite far from that of students A and B?

Match the following types of column chromatography with the underlying principle. Affinity chromatography HPLC lon-exchange chromatography (IEX) Size-exclusion chromatography ✓[Choose ] exploits differences in molecular size of individual proteins exploits differences in the size and magnitude of the net charge of individual proteins at specific pris requires a ligand (specific binding partner) to attract and retain a target protein relies on high pressure pumps that force proteins through a column [Choose] [Choose ]

4) If the classification of the chromatography run is a reverse-phase chromatography, discuss the relative polarities of caffeine, aspartame and benzoate.

The following sentence has the format “Statement 1 BECAUSE Statement 2”. Decide whether statement 1 is true, whether statement 2 is true, and whether the REASONING (the ‘BECAUSE’ relationship) between them is valid. Statement 1 − “Cyclohexane-1,2-diol elutes from a silica gel chromatography column after cyclohexane-1,2-dione” BECAUSE Statement 2 − “Ketones stick better to silica than alcohols because the C=O group has a larger dipole than the C-OH group.”   Question 6 options: A Statement 1 and Statement 2 are both correct, and the reasoning is valid.  B Statement 1 and Statement 2 are both correct, but the reasoning is NOT valid. C Statement 1 is correct, but Statement 2 is NOT correct.   D Statement 1 is NOT correct, but Statement 2 is correct. E Statement 1 and Statement 2 are both NOT correct

Which of the following chromatographic methods cannot use a mixture of liquid solvents (eluents) during the separation process?     Thin layer chromatography     High pressure liquid chromatography     Column chromatography     Gas chromatography

Dissolve 1 mL of clove oil in 2 mL of dichloromethane. Add 10 mL of aqueous sodium hydroxide (NaOH) solution. Shake and separate layers, keeping the organic layer (dichloromethane). Obtain a silica-packed chromatography column. Add 2 mL of hexane to the column, allow the solvent to just reach the top of the silica packing, then immediately add the dichloromethane layer that was separated earlier. Allow the organic layer to just reach the top of the silica packing, then immediately add 10 mL more of hexane. When the solvent just reaches the top of the silica packing, switch solvents by adding 10 mL of acetone. Switch to acetone. a) Which component of clove oil (eugenol, eugenyl acetate, or caryophyllene) ends up in the layer containing the NaOH? Explain your answer. b) Which component of clove oil (eugenol, eugenyl acetate, or caryophyllene) is pushed down the column by hexane, a non-polar solvent? Explain your answer. c) Which component of clove oil (eugenol, eugenyl acetate, or…

Use a suitable model to explain how separation and identification of a mixture of organic compounds can be achieved with a thin layer chromatographic (TLC) technique.

Please choose an appropriate technique(s) to separate following compounds (it can be one, more than one, on none): Compound Melting Point Density Boiling Point Molar mass Phenol 40.5°C 1.07 g/cm 181.7°C 94.113 g/mol Toluene -95 °C 0.87 g/mL 111 °C 92.141 g/mol Simple Filtration Column Chromatography Distilation Crystallization/Re-Crystallization Separatory funnel None www. MacBook Air