Chromatography

Question 1

what does paper chromatography do

Answer 1

• separates parts of mixture
• useful in identifying something

Question 2

uses of chromatography

Answer 2

• separating pigments, using the exact types of pigment to ID
• used in forensics, biology, chemistry
  ex: you want to find out what type of pen made a certain black ink spot or you want to find out which pigments a certain type of leaf has

Question 3

the sample will travel through a setup consisting of two things/phases (name + explain them)

Answer 3

1. Stationary phase: is made of a sample that is fixed and the sample must move through/past it
2. Mobile phase: is made of a type of solvent which the sample can move through

Question 4

what does the distance the various pigments will travel depend on

Answer 4

depend on its affinities (attraction) to each phase and also its size (smaller ones travel farther)

Question 5

facts about the retention factor (RF value)

Answer 5

• can be calculated as a means of comparing the different pigments
• each pigment, with the same combination of mobile and stationary phases, will always have the same calculated Rf value
• this allows us to compare different samples
• calculation: Rf = distance travelled y the pigment/distance travelled by solvent

Question 6

what does the type of chromatography depend on (+ex)

Answer 6

depends on what type of mixture you want to separate
ex: gas chromatography, thin layer chromatography, paper chromatography
(see paper chromatography set up on paper)

Question 7

what does it mean if you only get one spot that travels up the paper

Answer 7

means it only contains one substance (not a mixture)

Question 8

true or false: each pigment travels a different distance

Answer 8

true

Question 9

finding RF value

Answer 9

see paper

Question 10

true or false: the RF value is unique to each substance

Answer 10

true