Lab 11 Essay

378 WordsJul 6, 20122 Pages
Experiment 11 Lab Assignment Answer Sheet: Chromatography of Food Dyes Name: Pre-Lab: Define the Rf value of a compound The "rf" value is the distance the compound moves relative to the distance the solvent moves. Data and Observations: Record the distance travelled by the sample and the solvent in the table below and calculate the Rf values. Table 1. Color Distance(m Blue1 Blue2 Red3 Red40 Yellow5 Yellow6 33 3 10 22 42 30 .55 .05 .17 .37 .70 .50 m) Rf Solvent 60 Table 2. Kool-Aid®: Grape Kool-Aid®: Strawberry Distance (mm) Red: 5 10 Distance (mm) Blue:17 n/a Rf .08 and .28 .17 Substance Solvent 60 Table 3. Substance Distance McK Red McK Yellow McK Green McK Blue Solvent 51 60 Yellow-50 Red-33 80 Blue-72 Blue-70 80 .63 and .90 .41 and .88 (mm) Distance (mm) Rf .64 .75 Table 4. Substance M&M M&M M&M M&M Green Yellow Blue Red Distance (mm) 8 30 50 10 Rf .10 .38 .63 Solvent .13 A. 80 The FD&C color(s) making up the unknown = Blue #1, Red #40, Yellow #42 B. Brand name of the FD&C color(s) from the grocery store food = Blue #1, Red #40 C. The FD&C color(s) making up the grocery store food colorings = McKormicks- Yellow #42, Blue #1, Red #40 D. The FD&C color(s) making up the Kool-Aid drinks. = Grape= Red #3 and Blue #1, Strawberry= Red #3 E. The FD&C color(s) making up the M&M’s®. = Blue #1, Yellow #6, Red #3, Post-Lab Questions: 1.Why can't a pen be used to draw the baseline on the chromatography paper? Because the ink would separate. 2. Why is it important to stop the chromatograph before the solvent reaches the top of the paper ? Without knowing where the solvent reaches

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