Chemistry- Chromatography UPDATED
Exam Questions and CORRECT Answers
What is chromatography? - CORRECT ANSWER - Technique used to separate and
analyse substances present in the mixture
What are components? - CORRECT ANSWER - Substances present in the mixture that
are being seperated
What is a chromatogram? - CORRECT ANSWER - Patten of bands and sports
What happens to components in chromatography? - CORRECT ANSWER - As the
components in the ink are swept upwards over the stationary phase by the solvent, they undergo
a continual process of absorption onto solid stationary phase, followed by desorption and
dissolving into the mobile phase
What depends on the components to stick to the stationary phase? - CORRECT
ANSWER - The polarity of the stationary phase and the component molecules. The
attraction of the components to the solvent molecules is determined by their polarity.
What does the rate of movement of each component depend on and why do components
separate? - CORRECT ANSWER - 1. How strongly the component absorbs onto
stationary phase
2. How readily the component dissolves in the mobile phase
Components separate because they undergo these 2 processes to different degrees
What is absroption? - CORRECT ANSWER - Describes the adhesion of molecules or
substances to the surface of a solid or liquid
What is the stationary phase? - CORRECT ANSWER - Either liquid or solid
, What is the mobile phase? - CORRECT ANSWER - Either liquid or gas
How does polarity affect chromatography? - CORRECT ANSWER - Polar molecules in a
polar solvent will move up quickly with the solvent
What is paper chromatography? - CORRECT ANSWER - Performed on a high quality
absrobant paper, similar to filter paper, as the stationary phase.
What is thin layer chromatography? - CORRECT ANSWER - Uses a thin layer of fine
paper
What do TLC and paper chromatography provide? - CORRECT ANSWER - Qualitative
data for identifying chemicals present in a mixture
What is the origin? - CORRECT ANSWER - Small spot of the solution of the sample that
is to be analysed
What is the process of paper and TLC? - CORRECT ANSWER - 1. The origin is placed
on one end of the chromatography paper or plate
2. The paper or plate is then placed in an container with solvent. The origin must a little abode
the level of the solvent so that the components can be transported up the paper/plate and not
dissolve in the liquid in the container
3. As the solvent rises up the plate/paper, the components of each sample separate depending on
their attraction
How can components of a mixture be identified? - CORRECT ANSWER - 1. Including
standards of known chemicals on the same chromatogram as the unknown sample and
comparing the resulting positions of the unknown components with these known samples
2. The sample(known element) and standard(unknown element) are run on the same
chromatogram because the distances moved from the origin will depend on the distances moved
by the solvent front
Exam Questions and CORRECT Answers
What is chromatography? - CORRECT ANSWER - Technique used to separate and
analyse substances present in the mixture
What are components? - CORRECT ANSWER - Substances present in the mixture that
are being seperated
What is a chromatogram? - CORRECT ANSWER - Patten of bands and sports
What happens to components in chromatography? - CORRECT ANSWER - As the
components in the ink are swept upwards over the stationary phase by the solvent, they undergo
a continual process of absorption onto solid stationary phase, followed by desorption and
dissolving into the mobile phase
What depends on the components to stick to the stationary phase? - CORRECT
ANSWER - The polarity of the stationary phase and the component molecules. The
attraction of the components to the solvent molecules is determined by their polarity.
What does the rate of movement of each component depend on and why do components
separate? - CORRECT ANSWER - 1. How strongly the component absorbs onto
stationary phase
2. How readily the component dissolves in the mobile phase
Components separate because they undergo these 2 processes to different degrees
What is absroption? - CORRECT ANSWER - Describes the adhesion of molecules or
substances to the surface of a solid or liquid
What is the stationary phase? - CORRECT ANSWER - Either liquid or solid
, What is the mobile phase? - CORRECT ANSWER - Either liquid or gas
How does polarity affect chromatography? - CORRECT ANSWER - Polar molecules in a
polar solvent will move up quickly with the solvent
What is paper chromatography? - CORRECT ANSWER - Performed on a high quality
absrobant paper, similar to filter paper, as the stationary phase.
What is thin layer chromatography? - CORRECT ANSWER - Uses a thin layer of fine
paper
What do TLC and paper chromatography provide? - CORRECT ANSWER - Qualitative
data for identifying chemicals present in a mixture
What is the origin? - CORRECT ANSWER - Small spot of the solution of the sample that
is to be analysed
What is the process of paper and TLC? - CORRECT ANSWER - 1. The origin is placed
on one end of the chromatography paper or plate
2. The paper or plate is then placed in an container with solvent. The origin must a little abode
the level of the solvent so that the components can be transported up the paper/plate and not
dissolve in the liquid in the container
3. As the solvent rises up the plate/paper, the components of each sample separate depending on
their attraction
How can components of a mixture be identified? - CORRECT ANSWER - 1. Including
standards of known chemicals on the same chromatogram as the unknown sample and
comparing the resulting positions of the unknown components with these known samples
2. The sample(known element) and standard(unknown element) are run on the same
chromatogram because the distances moved from the origin will depend on the distances moved
by the solvent front
