TLC

Question 1

chromatography is a method for…

Answer 1

• identification
• isolation
• purification

Question 2

what is the main function for thin layer chromatography

Answer 2

• comparing/identifying unknown compounds
• useful for monitoring reactions

Question 3

what is the stationary phase in TLC and is it polar or nonpolar

Answer 3

the stationary phase is the coating on the hard back of the TLC plate. The stationary phase is what the mobile phase adhears to as it carries the sample up the TLC plate.

the stationary phase is polar

Question 4

what is the mobile phase in TLC and is it polar or nonpolar

Answer 4

the mobile phase is the solvent that the sample is dissolved in. the mobile phase carries the samples up through the stationary phase (coating)

the mobile phase is nonpolar

Question 5

what does it mean if a dot is lower on the TLC plate

Answer 5

the compound in that dot is more polar, so it has a higher affinity for the polar stationary phase

Question 6

what does it mean if a dot is higher on the TLC plate

Answer 6

the compound in that dot is more nonpolar and has a higher affinity for the nonpolar mobile phase

Question 7

what happens if the solvent (mobile phase) is too nonpolar or too polarin TLC

Answer 7

the dots will not separate

Question 8

what happens if the solvent is too polar

Answer 8

the dots will move too far up the TLC plate

Question 9

what happens if the solvent is too nonpolar

Answer 9

the dots wil hardly move off the baseline

Question 10

what is the equation for Rf values

Answer 10

(distance that the spot travelled) / (distance that the solvent travelled)