3.5 Chemical Analysis

Question 1

3.5a- Chromatography

What happens during Chromatography?

Answer 1

The components of a mixture are separated due to differences in the polarity &/or size of molecules

Question 2

3.5a- Chromatography

Separation depende on the equilibrium between what 2 phases?

Answer 2

• Mobile phase
• Stationary phase

Question 3

3.5a- Chromatography

Paper Chromatography

Answer 3

• Stationary phase: Paper
• Mobile phase: Solvent

Question 4

3.5a Chromatography

Substances will travel further if…

Paper Chromatography

Answer 4

They are more soluble in the solvent

Question 5

3.5a- Chromatography

How many values on a paper chromatography sample?

Answer 5

Always 5

Question 6

3.5a- Chromatography

Gas-Liquid Chromatography

Answer 6

• Stationary phase: High bpt liquid held in inert powdered support material, packed into coiled column in an oven
• Mobile phase: Inert gas e.g Helium or Nitrogen

Question 7

3.5a- Chromatography

What chemicals have higher affinity for the mobile phase?

Answer 7

Those with shorter retention times

Question 8

3.5a- Chromatography

What do the following mean?
* Height of peaks
* Retention time

Gas Chromatography

Answer 8

• Relative concentration of substance
• The affinity the substance has for the mobile phase

Question 9

3.5a- Chromatography

Define: “Inert”

Answer 9

Unreactive

Question 10

3.5b- Volumetric Titrations

Define: “Standard Solution”

Answer 10

A solution of accurately known concentration

Question 11

3.5b- Volumetic Titrations

Why are substances such as Potassium Permanganate useful in titrations?

Answer 11

They can act as their own indicators