Transcription
Lab #1: Paper ChromatographyTo separate a mixture using paper chromatography.Vocabulary Words: Chromatography Homogeneous Mixture Stationary Phase Mobile Phase Analyte Solvent ConstituentThere are 3 primary colors: Red, Blue & Yellow. Most colors are produced by mixing two ormore primary colors together.Ex. Green color is produced by mixing blue & yellow.In paper chromatography, small samples of analytes are spotted onto chromatography paper,which serves as stationary phase. A liquid mobile phase is wicked up the stationary phase bycapillary action, causing the analytes to move upward. The distance traveled by each analytedepends on its affinity for the mobile phase. The higher the affinity the farther it will travel. Onthe other hand, if the particular analyte has a higher affinity for the stationary phase than tothe mobile phase, then it will stick to the stationary phase and not travel as far. The ration ofthe distance traveled by an ink “spot” (analyte) to the distance traveled by the solvent (mobilephase) is called retention factor, Rf. *% (,(! -. /&%,. (Rf !"# %&'(!"# %&'( *% (,(! -. 01, (& Black inkFilter PaperMetric RulerClear TapePencilIsopropyl AlcoholDI Water250 ml Beaker TimerCamera to Record1. Obtain Filter Paper and 250 ml Beaker2. Measure and cut 12 cm of Filter Paper3. Measure 1 cm from the base of the Filter Paper and make a straight line across using a pencil.xxxxpg. 1
Lab #1: Paper Chromatography4. Obtain a pencil and a tape. Attach the filter paper to the pencil such that when the pencil is restedon the rim of the beaker, the filter paper barely touches the bottom of the beaker.xxxxxxxx5. Add 5 mL of isopropyl alcohol to 250 mL of beaker.6. Use the assigned 4 black markers to make the spots on the filter paper.(Warning: The ink should be at least 3 mm from the edge of the filter paper, since liquids travel faster on the edges of apaper. Can you think of why placing ink on the edge of the paper will cause an experimental error and unsuccessfulseparation of colors).xxxx7. REST the pencil-filter paper setup on the rim of the beaker with isopropyl alcohol.5 mL ofIsopropylAlcoholxxxx8. Observe and Record !pg. 2
Lab #1: Paper ChromatographyData Table 1: Assigned Black InksBlack InkAssigned BlackInk #Black Ink Information1.2.3.4.Data Table 2: ObservationsBlack InkAssignedBlack Ink#Observations in1 min.Observations in5 min.Observations in15 min.Observations in25 min.1.2.3.4.(Keep in mind that a few variations of the experimental procedure might be observed).Example #1.(Note: did not use pencil)Example #2.(Note: Then only used 3 Different Black Inks)pg. 3
Lab #1: Paper Chromatography(Note: You must calculate retention factor for each primary color of each black ink).Use the following example to complete your calculations for each of the black inks assigned to yourgroup: *% (,(! -. /&%,. (Rf !"# %&'(!"# %&'( *% (,(! -. 01, (& 1) Black Ink #Distance that MobilePhase Traveled (Solvent)6 cm5 cmDistance Blue DyeTraveledDistance Pink DyeTraveled2 cm0 cmOriginal position of theblack inkRf (BlueDye) 2.4 '5.6.4 '5 0.83Rf (PinkDye) 7.4 '5.6.4 '5 0.33Rf (YellowDye) 86.4 '5 Repeat this Calculation for all 4 Black Ink Results.2) Black Ink #3) Black Ink #4) Black Ink #MandatoryWatch:Khan AcademyCalculating Retention Factorfor T.L.C.pg. 4
Lab #1: Paper ChromatographyAnswer questions # 1-131. Restate and clarify the purpose of this lab in your own words including “what will be analyzed,the technique that will be used and what is it that we were trying to accomplish. 1-2 sentences.2. What is analyte? (definition in your own words)3. Which substance/substances are considered analyte(s) in this lab? (Temperature, beaker, filterpaper etc.)4. How many analytes did you use in this lab?5. Identify this(these) analyte(s).6. In your own words, write the summery of the process of paper chromatography. (How did youconduct this experiment?)7. Identify each item of the lab as stationary phase, mobile phase, solvent and analyte.8. Was your experiment successful?9. Identify possible source of errors.a.b.c.10. Report your results (your final observation for each analyte).AnalyteName or AnalyteNumber1.2.3.4.pg. 5
Lab #1: Paper Chromatography11. Report all the values of Rf and explain what they mean in terms of degree affinity towardsstationary or mobile phase. (use your knowledge of paper chromatography technique. See thebackground info provided for this lab).Black Ink#Dye ColorRf ValuesExplain1.2.3.4.12. Explain why Rf does not have units such as cm, m, km, etc.(Hint: the answer lies in Rf formula)13. Do all blue dyes separated from the 4 analytes tested have the same Rf values? What does thistell you about the molecular shapes of those blue dyes?14. Are these analytes consider to be Homogeneous or Heterogeneous mixtures? Explain.pg. 6
In paper chromatography, small samples of analytes are spotted onto chromatography paper, which serves as stationary phase. A liquid mobile phase is wicked up the stationary phase by capillary action, causing the analytes to move upward. The distance traveled by each analyte depends on its affinity for the mobile phase. The higher the affinity the farther it will travel. On
