Chapter 29: Chromatography and spectroscopy

Question 1

what is chromatography used for

Answer 1

to separate a mixture into its components and identify these

Question 2

what are the two phases in chromatography

Answer 2

stationary and mobile

Question 3

describe the stationary phase

Answer 3

the substance does not move and is normally supported by a solid or a liquid

Question 4

describe the mobile phase

Answer 4

the substances do move normally in liquid or gaseous form

Question 5

what substance does TLC normally require on the plate and why

Answer 5

silica because it is non reactive and adsorbent

Question 6

what does the Rf value/ how far the substance travel depend upon

Answer 6

affinity for the solvent

Question 7

what is the Rf equation

Answer 7

Rf = (distance moved by the component) / (distance moved by the solvent front)

Question 8

what is Gas Chromatography useful for

Answer 8

separating and identifying volatile organic mixtures

Question 9

what happens during the stationary phase of Gas Chromatography

Answer 9

a high bp liquid is adsorbed onto an inert solid support

Question 10

what happens during the mobile phase of Gas Chromatography

Answer 10

inert carrier gas such as helium or neon is added

Question 11

what is the first step of gas chromatography

Answer 11

the volatile mixture is inserted into the gas chromatogram (oven)

Question 12

what is the second step of gas chromatography

Answer 12

the mobile carrier gas carries the components through the capillary column which contains the liquid stationary phase on a solid support

Question 13

what is the third step of gas chromatography

Answer 13

the different components slow down at different speeds separating them