RP 8

Question 1

invstigating pigments released from leaves.
Collecting plant samples

Answer 1

1. no damage to leaf
2. diff colour leaves
3. large sample so representative

Question 2

Why you add a lid on tank?

Answer 2

prevent evaporation of tank

Question 3

Why use a pencil?

Answer 3

origin line is visible and pencil doesnt dissolve

Question 4

Negative and positive controlNegative control:

Answer 4

-Negative control: Perform the chromatography using a blank filter paper strip without any pigmented extract to determine if any pigments are present naturally in the solvent or filter paper.

Positive control: Use a known pigment (e.g., chlorophyll) to verify its expected migration and retention factor values.

Question 5

How deep is the solvent submerged ? IS it touching origin line?

Answer 5

-1cm
-NO its below

Question 6

Chromatography limitation , what is better?

Answer 6

-only qualitative

Question 7

Safety precaution .

Answer 7

-wear gloves
-solvents could be toxic
-fume cup

Question 8

How do you identify pigments .(2)

Answer 8

-calculate Rf value
-distance moved by pigment/ solvent front
-comparing to Rf value of known pigment

Question 9

What is the role of solvents in this experiment?

Answer 9

-Solvents are used to dissolve the pigments present in the plant samples

Question 10

Why is it important to mark location of each spot immediately?

Answer 10

1.once dried u cannot see solvent front/colour fades of pigs

Question 11

Why Rf value is better rather than js distance moved?

Answer 11

1. Constant
   2.ratio of x:x
   3.solvent moves diff distances

Question 12

-Not move bottle
-why centre of spot

Answer 12

1.pigment wouldn’t go straight
2.standardised proced
3.allow comparison

Question 13

Thicker leaves?

Answer 13

-harder to crush
-less conc of pigment